# StudyKit > StudyKit is a free collection of browser-based tools for writing, study, documents, images, QR codes, screenshots, and audio. No account is required. Most tools run entirely in the browser; the few that upload a file say so before you start. ## Tools ### Text - [Text Rewriter](https://studykittools.com/tools/ai-text-humanizer/): Rewrite a paragraph so the wording reads differently without changing the meaning. - [Prompt Builder](https://studykittools.com/tools/ai-prompt-optimizer/): Turn a lazy prompt into a proper brief with a role, context, format and rules, for ChatGPT, Claude, Midjourney or anything else. - [Writing Pattern Analyser](https://studykittools.com/tools/writing-pattern-analyser/): Measure sentence length variation, vocabulary range, repetition and passive voice in any text. - [Invisible Character Cleaner](https://studykittools.com/tools/invisible-character-cleaner/): Find and remove zero-width characters, bidirectional controls and soft hyphens from copied text. - [Alphabetical Order Tool](https://studykittools.com/tools/alphabetical-order-tool/): Sort any list of words or names from A to Z or Z to A, in your browser. - [Punctuation Fixer](https://studykittools.com/tools/pdsf/): Repair doubled spaces and repeated punctuation in copied text. - [Case Converter](https://studykittools.com/tools/case-converter/): Switch text between sentence case, lower case, and UPPER CASE. - [Citation & Bibliography Generator](https://studykittools.com/tools/citation-generator/): Format a reference in APA, MLA, Chicago or Harvard, and export it as BibTeX. ### Counting & Analysis - [Word Counter](https://studykittools.com/tools/word-counter/): Count words, characters, sentences, and paragraphs as you type. - [Reading Time](https://studykittools.com/tools/reading-time/): Estimate how long a piece of writing takes to read or to say aloud. - [Keyword Density](https://studykittools.com/tools/word-frequency-keyword-density-counter/): See which words a text leans on most, and how often. ### Images - [Image Compressor](https://studykittools.com/tools/image-compressor/): Make a picture smaller for email or the web, and see the saving. - [Text from Image](https://studykittools.com/tools/image-to-text-ocr/): Pull typed words out of a photo or a scan so you can copy them. - [Resize Image](https://studykittools.com/tools/image-resize-social/): Resize a picture to the sizes social platforms ask for. - [Aspect Ratio](https://studykittools.com/tools/image-aspect-ratio-converter/): Change a picture's shape without stretching it. - [WebP to JPG or PNG](https://studykittools.com/tools/webp-to-jpg-png/): Convert a WebP picture into a format everything else accepts. - [Blur & Pixelate](https://studykittools.com/tools/image-blur/): Blur a picture to hide a face, a plate number, or a screen. - [Colour Picker](https://studykittools.com/tools/image-color-picker/): Pick a colour from a picture and get its hex and RGB values. - [Add a Watermark](https://studykittools.com/tools/image-watermark/): Put your own mark across a picture to show it is yours. - [Background Remover](https://studykittools.com/tools/background-remover/): Cut the background out of an image. The model runs in your browser, so the picture is never uploaded. - [Redact Image](https://studykittools.com/tools/image-redaction-metadata-cleaner/): Cover personal details in a picture and clear its saved location data. - [Colour Palette Generator](https://studykittools.com/tools/colour-palette-generator/): Pull the colours out of a picture, with the contrast of each pair worked out. ### PDF & Documents - [Word to PDF](https://studykittools.com/tools/pdf-converter/): Turn a .docx into a PDF in your browser. Content is kept; exact page layout is not. - [Split PDF](https://studykittools.com/tools/split-pdf/): Pull pages or page ranges out of a PDF into separate documents, in your browser. - [Merge PDF](https://studykittools.com/tools/merge-pdf/): Combine several PDFs into one file, in the order you choose. - [PDF Editor](https://studykittools.com/tools/pdf-editor/): Reorder, rotate, duplicate, or delete pages, then download the file. - [PDF to EPUB](https://studykittools.com/tools/pdf-to-epub/): Turn a text-based PDF into an EPUB that reflows on an e-reader. ### QR Codes - [URL QR Code](https://studykittools.com/tools/url-qr-generator/): Turn a web address into a code anyone with a phone can scan. - [Text QR Code](https://studykittools.com/tools/text-qr-generator/): Put any short piece of text into a scannable code. - [Email QR Code](https://studykittools.com/tools/email-qr-generator/): Make a code that opens a new message to an address. - [Wi-Fi QR Code](https://studykittools.com/tools/wifi-qr-generator/): Make a code that joins someone to a network without typing it. - [QR Code Scanner](https://studykittools.com/tools/qr-scanner/): Read a code with the camera and see what it holds. ### Calculators - [GPA Calculator](https://studykittools.com/tools/gpa-calculator/): Work out a weighted grade point average from credits and grades. - [Percentage Calculator](https://studykittools.com/tools/percentage-calculator/): Work out percentages, differences, and increases. ### Capture & Record - [Screenshot](https://studykittools.com/tools/screenshot-capture/): Capture a tab, a window, a screen, or a selected area as a PNG. - [Screen Recorder](https://studykittools.com/tools/screen-recorder/): Record the screen, with an optional microphone, in your browser. ### Video - [Video Auto Clip](https://studykittools.com/tools/video-auto-clip/): Find the interesting parts of a video and cut them into separate clips. ### Study & Recall - [Study Planner](https://studykittools.com/tools/study-planner/): Turn subjects and an exam date into a revision timetable that spreads each subject across the weeks you have. - [Cornell Notes Generator](https://studykittools.com/tools/cornell-notes-generator/): Lay notes out on the Cornell pattern with a cue column and a summary band, ready to print. - [Quiz Generator](https://studykittools.com/tools/quiz-generator/): Turn notes into a self-marking quiz, or print an answer sheet to write on. - [Study Guide Builder](https://studykittools.com/tools/ai-study-guide-generator/): Turn a passage into named guide sections with a check question each, using a model that runs on this server. - [Flashcards](https://studykittools.com/tools/flashcards/): Make flashcards from your notes and study them with active recall. ### Audio - [Audio Compressor](https://studykittools.com/tools/audio-compressor/): Shrink an audio file to MP3 or WAV with the encoder running in your browser. Nothing is uploaded. ### Trading practice - [Crypto Chart Simulator](https://studykittools.com/tools/crypto-chart-simulator/): Practise reading live crypto charts, or replay history candle by candle, with a simulated balance. ## Guides - [How to choose a course of study](https://studykittools.com/guides/choosing-a-program/): Choose a course by starting from the work you want to do, then check whether the profession is regulated, what the board exam involves, and what the total cost will be. The subject you enjoy matters, but it is not enough on its own. - [Licences and board exams: know this before you enrol](https://studykittools.com/guides/licenses-and-registrations/): In the Philippines, many professions require a PRC licensure exam before you can practise. Before you enrol, check the regulator, the exam pass rate, the total cost, and whether the programme is accredited. - [Getting an internship](https://studykittools.com/guides/getting-an-internship/): A legitimate internship has a written description, a named supervisor, and a schedule. In the Philippines, unpaid internships must also meet the conditions in Article 306 of the Labor Code; never pay a fee for the privilege of working. - [Studying abroad: how to evaluate an agency, and what to check yourself](https://studykittools.com/guides/studying-abroad/): A study-abroad agency can help with applications, documents, and visas, but you should still verify the institution, the programme, and CHED recognition yourself. Ask who pays the agency before you rely on its advice. - [Overseas internships](https://studykittools.com/guides/overseas-internships/): A real overseas internship is sponsored by the employer, holds the correct work authorisation, does not charge you for the placement, and has a named supervisor. Confirm the visa rules with your own country's embassy or consulate, and with its overseas labour body if it has one, before paying anyone. - [Student internships](https://studykittools.com/guides/internships/): Student internships should be structured placements with a written agreement and a named supervisor. In the Philippines, unpaid internships must meet Article 306 conditions, including at least 20 hours a week and no more than 8 hours a day. - [Study abroad](https://studykittools.com/guides/study-abroad/): Before paying a study-abroad agency, check four things: the institution exists, your qualification will be recognised by CHED, the programme is registered in that country, and you know who pays the agency. The directory shows what has been verified and what has not. - [Free courses and certificates](https://studykittools.com/guides/providers/): Free courses usually make the lessons free and charge for the certificate. Check who issues the certificate, what recognition it has, and whether the provider paid for the listing before you spend anything. - [Financial guide for students](https://studykittools.com/guides/finance/): Student money problems usually come from a total cost that was never stated or a signature that made you responsible for someone else's debt. Ask for the total as a schedule, not a rate, and read what a co-maker promises before signing. - [Marketing guide for students](https://studykittools.com/guides/marketing/): A marketing claim is a statement that can be checked, so it needs a source rather than a tone. Define your audience by what it is trying to do, keep a source you could produce on request, and remember that consent is part of the channel. ## Articles Index: [Articles](https://studykittools.com/blog/articles/) - [How Many Words Is a 5-Minute Speech?](https://studykittools.com/blog/articles/how-many-words-is-a-5-minute-speech/): A five-minute speech is about 650 words at a normal pace of 130 words per minute, with a useful range of 550 to 800 words. Measure your own pace with a timed 150-word sample. - [Merge PDFs Without Uploading Them](https://studykittools.com/blog/articles/merge-pdf-without-uploading/): Merging PDFs in the browser reads the files on your device and never uploads them. You can test the claim by disconnecting from the network: a local merger still works, while an upload-based tool fails. - [Passport Photo Sizes by Country (Philippines, US, UK & More)](https://studykittools.com/blog/articles/passport-photo-size/): Philippine passport photos are 35 × 45 mm (413 × 531 px at 300 dpi); US passport photos are 2 × 2 in (600 × 600 px). Check the form you are actually submitting, because visa and ID photos can differ from the general rule. - [How to Rewrite AI Text Without Changing What It Says](https://studykittools.com/blog/articles/ai-text-humanizer-guide/): Keep names, numbers and claims intact when you reword a draft: mark what must survive, rewrite in small sections, and compare each one with the original. - [How to Rewrite Text for a Different Audience](https://studykittools.com/blog/articles/how-to-rewrite-text-for-a-different-audience/): A practical method for changing tone, jargon, and level of detail without changing the facts or the point of the original text. - [How to Tighten a Wordy Paragraph Without Cutting the Point](https://studykittools.com/blog/articles/how-to-tighten-a-wordy-paragraph/): Find the sentence underneath the extra words, remove the padding, and keep the evidence that makes your own claim stand up. - [How to Write a Prompt That Gets a Useful Answer](https://studykittools.com/blog/articles/ai-prompt-optimizer-guide/): A useful prompt names a role, gives the context that matters, states the task in one sentence, and fixes the output format before you ask for anything. - [Prompt Structure: Role, Context, Format, and Rules](https://studykittools.com/blog/articles/prompt-structure-role-context-format/): A repeatable prompt structure that tells an AI model who it is writing for, what matters, and what the answer must look like exactly. - [How to Write Prompts for Image Generators](https://studykittools.com/blog/articles/how-to-write-prompts-for-image-generators/): Describe the subject, framing, light, and style in a way an image model can act on, then change only one variable at a time. - [What a Writing Pattern Analyser Can Tell You About Your Draft](https://studykittools.com/blog/articles/writing-pattern-analyser-guide/): A pattern analyser measures how your sentences vary in length, how often you repeat yourself, and how much of your draft leans on the passive voice. - [Sentence Length Variation and Why It Affects Readability](https://studykittools.com/blog/articles/sentence-length-variation-and-readability/): Readable prose varies its sentence length on purpose, so the reader gets short sentences to rest on and longer ones that carry the argument. - [How to Spot Passive Voice in Your Own Writing](https://studykittools.com/blog/articles/how-to-spot-passive-voice-in-your-own-writing/): Passive voice hides the actor, and the tell is a form of "to be" followed by a past participle, which is easier to find in your own drafts than you expect. - [How to Remove Invisible Characters from Copied Text](https://studykittools.com/blog/articles/invisible-character-cleaner-guide/): Copied text can carry zero-width characters, non-breaking spaces and soft hyphens that look like nothing but break searches, forms and code. - [What Zero-Width Characters Do to Your Text](https://studykittools.com/blog/articles/what-zero-width-characters-do-to-your-text/): Zero-width characters are real Unicode characters with no visual width, used for line breaking and emoji joining, and they break exact matching when unwanted. - [Why Copied Text Breaks Forms and Searches](https://studykittools.com/blog/articles/why-copied-text-breaks-forms-and-searches/): Copied text fails in forms and searches because it carries invisible characters and non-standard spaces that the receiving field compares literally. - [How to Alphabetize Names, Titles, and Lists Correctly](https://studykittools.com/blog/articles/alphabetical-order-tool-guide/): Alphabetical order depends on rules, not just letters: decide how to treat spaces, articles, name particles and numbers, then apply the same rule throughout. - [Alphabetical Order Rules for Numbers, Hyphens, and Articles](https://studykittools.com/blog/articles/alphabetical-order-rules-numbers-hyphens-articles/): How to handle numbers, symbols, hyphenated names, and leading articles when a list has to be alphabetised consistently and fairly. - [How to Sort a List in Excel, Google Sheets, and Word](https://studykittools.com/blog/articles/how-to-sort-a-list-in-excel-google-sheets-and-word/): Sort a column without scrambling its neighbours, fix the usual causes of a wrong order, and know when a dedicated tool is faster. - [How to Fix Double Spaces and Repeated Punctuation](https://studykittools.com/blog/articles/pdsf-guide/): Doubled spaces and repeated punctuation are easy to fix, but the exceptions matter: keep deliberate ellipses, clean the rest, and proofread the result. - [Why Pasted Text Has Double Spaces and How to Clean It](https://studykittools.com/blog/articles/why-pasted-text-has-double-spaces/): Where the extra spaces come from, why they survive a copy and paste, and how to remove them from the source without breaking the text. - [Comma Splices, Run-ons, and Fragments: A Quick Fix Guide](https://studykittools.com/blog/articles/comma-splices-run-ons-and-fragments/): Three common sentence errors, how to recognise each one, and the simplest repairs that keep your meaning intact in formal prose. - [Title Case, Sentence Case, or UPPERCASE: When to Use Each](https://studykittools.com/blog/articles/case-converter-guide/): Use sentence case for running text and most web headings, title case for titles under a style guide, and uppercase only for short labels or warnings. - [Title Case Rules for Headings, Book Titles, and Job Titles](https://studykittools.com/blog/articles/title-case-rules-for-headings-and-titles/): Which words to capitalise in a title, which to leave lower case, and why style guides disagree about short words in your document. - [How to Change Text Case in Word, Google Docs, and Excel](https://studykittools.com/blog/articles/how-to-change-text-case-in-word-google-docs-and-excel/): Use the built-in case commands in the main writing apps, and know when a dedicated converter is the cleaner option safely. - [APA, MLA, Chicago, or Harvard: Choosing a Citation Style](https://studykittools.com/blog/articles/citation-generator-guide/): APA and Harvard use author-date, MLA favours author-page, and Chicago offers notes or author-date; pick the style your course or publication requires. - [How to Cite a Website in APA, MLA, and Harvard](https://studykittools.com/blog/articles/how-to-cite-a-website-in-apa-mla-and-harvard/): The elements a website citation needs, how the three common styles order them, and what to do when a page has no date correctly. - [How to Cite AI Chatbots and Generated Images](https://studykittools.com/blog/articles/how-to-cite-ai-chatbots-and-generated-images/): What to record when a source was produced by an AI tool, and why the rules are still changing across citation styles today. - [Word Count vs Character Count: Which Limit Applies?](https://studykittools.com/blog/articles/word-count-vs-character-count/): Words and characters answer different questions, and a form that asks for one will not accept the other. Here is how to check before you submit. - [How to Count Words in Google Docs, Word, and PDFs](https://studykittools.com/blog/articles/how-to-count-words-in-google-docs-word-and-pdfs/): Where to find the count in each app, what the number includes, and why a PDF often needs a different approach from the source file. - [How Long Does It Take to Read 1,000 Words?](https://studykittools.com/blog/articles/reading-time-guide/): At a typical reading pace of 200 to 250 words a minute, 1,000 words takes about four to five minutes; reading aloud takes closer to seven or eight. - [Average Reading Speed: What the Numbers Really Mean](https://studykittools.com/blog/articles/average-reading-speed-by-age-and-language/): The usual words-per-minute figures, the factors that change them, and why a reading-time estimate is a planning tool rather than a rule. - [How to Make a Long Article Easier to Read](https://studykittools.com/blog/articles/how-to-make-long-articles-easier-to-read/): Structure, headings, paragraph length, and summaries that help a reader finish a long piece without losing the argument. - [What Keyword Density Actually Tells You](https://studykittools.com/blog/articles/word-frequency-keyword-density-counter-guide/): Keyword density shows how often a term appears relative to the whole text. It is a useful editing signal, but a poor measure of relevance or quality. - [How to Find the Main Idea of a Text with Word Frequency](https://studykittools.com/blog/articles/how-to-find-the-main-idea-of-a-text/): Use repeated words as clues to the topic, then read the sentences around them to find the claim the text is actually making. - [Keyword Stuffing: How to Spot It and Fix It](https://studykittools.com/blog/articles/keyword-stuffing-how-to-spot-and-fix-it/): The signs of keyword stuffing, why repetition weakens a page, and how to rewrite it around the reader’s question instead of a phrase. - [How to Compress an Image Without Making It Look Bad](https://studykittools.com/blog/articles/image-compressor-guide/): Resize first, compress second: how to shrink a photo for email or the web while keeping edges, text, and skin detail looking clean. - [Why Image File Sizes Get So Large](https://studykittools.com/blog/articles/why-image-file-sizes-get-so-large/): Pixel count, colour depth, format, and scene detail all add to an image file; here is which factor is making yours large and what to do. - [How to Compress Images for Email, Websites, and Forms](https://studykittools.com/blog/articles/how-to-compress-images-for-email-websites-and-forms/): Resize for the destination first, then choose a format and compress; a practical workflow for email, websites, and strict upload forms. - [How OCR Turns a Photo into Editable Text](https://studykittools.com/blog/articles/image-to-text-ocr-guide/): OCR needs contrast, a straight page, and even light more than resolution; here is how it reads a photo and where it goes wrong. - [How to Improve OCR Accuracy: Lighting, Angle, and Resolution](https://studykittools.com/blog/articles/how-to-improve-ocr-accuracy/): Straight angles, even light, sharp focus, and sensible cropping do more for OCR accuracy than a higher pixel count. Here is how to apply them. - [How to Make a Scanned PDF Searchable](https://studykittools.com/blog/articles/how-to-make-a-scanned-pdf-searchable/): A scanned PDF is a set of page images; OCR adds the searchable text layer. Here is how to choose the right route and check the result. - [Social Media Image Sizes: A Practical Cheat Sheet](https://studykittools.com/blog/articles/social-media-image-sizes-cheat-sheet/): Use the right shape for each placement, keep the subject central, and check current platform guidance rather than trusting a fixed size table. - [How to Resize a Photo Without Stretching It](https://studykittools.com/blog/articles/how-to-resize-a-photo-without-stretching-it/): Lock the aspect ratio, crop or pad when the shape must change, and start from the largest original to resize a photo without distorting it. - [Crop or Resize? How Aspect Ratio Changes a Photo](https://studykittools.com/blog/articles/image-aspect-ratio-converter-guide/): Cropping changes a photo's shape, resizing changes its pixel count; choosing the right one keeps faces and subjects from being squashed. - [Common Aspect Ratios and Where to Use Them](https://studykittools.com/blog/articles/common-aspect-ratios-and-where-to-use-them/): From 1:1 squares to 21:9 banners, a plain guide to the common aspect ratios and the placements, prints, and screens each one suits. - [How to Crop an Image to an Exact Size for a Form](https://studykittools.com/blog/articles/how-to-crop-an-image-to-an-exact-size/): Crop to the required ratio, resize to the exact pixel count, then compress only if the limit demands it: a reliable order for form photos. - [WebP, JPG, or PNG: Which Image Format Should You Use?](https://studykittools.com/blog/articles/webp-to-jpg-png-guide/): WebP is small and web-friendly, JPG opens anywhere, and PNG keeps transparency and text sharp; pick the format that fits the destination. - [Why a WebP File Won’t Open (and How to Convert It)](https://studykittools.com/blog/articles/why-webp-files-wont-open/): A WebP file that will not open is often intact; the program lacks support for the format, and converting a copy to JPG or PNG usually fixes it. - [When to Keep WebP and When to Convert to JPG or PNG](https://studykittools.com/blog/articles/when-to-keep-webp-and-when-to-convert/): Keep WebP for your own website, and convert to JPG or PNG when a photo, form, printer, or older program needs a format it can open. - [How to Blur a Face, Plate Number, or Address in a Photo](https://studykittools.com/blog/articles/image-blur-guide/): A strong blur or an opaque block hides a face or plate; a weak one does not, and neither removes the location data saved in the file. - [How to Blur Sensitive Information in a Screenshot](https://studykittools.com/blog/articles/how-to-blur-sensitive-information-in-a-screenshot/): Find every identifying detail in a screenshot, cover text with an opaque block, and check the exported file before you share it anywhere. - [Blur, Pixelate, or Black Box: Which Redaction Is Safe?](https://studykittools.com/blog/articles/blur-vs-pixelate-vs-black-box/): A solid opaque block is the safest redaction for text and numbers; blur and small-block pixelation can sometimes be reversed or partially recovered. - [How to Pick a Colour from an Image and Use Its Hex Code](https://studykittools.com/blog/articles/image-color-picker-guide/): Sample a flat, evenly lit patch rather than an edge or highlight, and a hex code becomes a colour you can actually reuse on screen. - [Hex, RGB, and HSL: What Colour Codes Mean](https://studykittools.com/blog/articles/hex-rgb-hsl-color-codes-explained/): Hex, RGB, and HSL are three ways to write the same screen colour; the differences matter when you need to adjust or reproduce it. - [How to Match a Brand Colour from a Logo or Photo](https://studykittools.com/blog/articles/how-to-match-a-brand-colour-from-a-logo/): Sample flat areas of a logo, ignore edges and highlights, and confirm the hex value against a brand guide before using it for print or web. - [How to Watermark a Photo Without Ruining It](https://studykittools.com/blog/articles/image-watermark-guide/): A watermark should be readable at display size, hard to crop away, and quieter than the photo; placement, opacity, and a clean master matter. - [Where to Place a Watermark on a Photo](https://studykittools.com/blog/articles/where-to-place-a-watermark-on-a-photo/): Place a watermark where a crop cannot remove it without losing the subject, and check that it stays readable at the size people will see. - [Watermark or Copyright Notice: What Protects a Photo?](https://studykittools.com/blog/articles/watermark-vs-copyright-notice/): A watermark makes reuse visible and a copyright notice states ownership, but neither prevents copying or replaces legal advice. - [How Background Removal Works, and When It Fails](https://studykittools.com/blog/articles/background-remover-guide/): Background removal keeps the subject and makes the rest transparent; plain backgrounds and sharp edges work, hair and glass usually do not. - [How to Take a Clean Product Photo for Background Removal](https://studykittools.com/blog/articles/how-to-take-a-clean-product-photo-for-background-removal/): A clean product photo starts with a plain background, even lighting, and square framing that make the automatic cut-out easier to work with. - [Transparent PNG or White Background: When to Use Each](https://studykittools.com/blog/articles/transparent-png-vs-white-background/): Choose a transparent cut-out or a white background by looking at where the image will appear, how it will be printed, and which format supports it. - [Redacting a Photo: What to Cover and What to Strip](https://studykittools.com/blog/articles/image-redaction-metadata-cleaner-guide/): Cover faces, plates, and screens with an opaque block, then strip the location and device data; one without the other still leaks detail. - [How to Remove Location Data from a Photo](https://studykittools.com/blog/articles/how-to-remove-location-data-from-a-photo/): Strip GPS and device details from a photo, then check the image itself for visible clues that metadata removal cannot hide. - [How to Redact a Screenshot Before Posting It](https://studykittools.com/blog/articles/how-to-redact-a-screenshot-before-posting/): Find the details a screenshot leaks, cover text with solid blocks instead of blur, and strip file metadata before you publish the copy. - [How to Build a Colour Palette from a Photo](https://studykittools.com/blog/articles/colour-palette-generator-guide/): A practical guide to pulling a usable colour palette out of a photo, giving each swatch a role and checking contrast before you commit. - [Colour Harmony: Complementary, Analogous, and Triadic Palettes](https://studykittools.com/blog/articles/colour-harmony-complementary-analogous-triadic/): Compare three classic colour relationships, see what each one is good at, and learn how to turn a harmony into a palette that still reads clearly. - [How to Check Colour Contrast for Accessible Text](https://studykittools.com/blog/articles/how-to-check-colour-contrast-for-accessible-text/): Measure the contrast of the colours that really render, apply the WCAG thresholds for text and controls, and know what a pass does not prove. - [Word to PDF: Why the Layout Shifts and How to Keep It](https://studykittools.com/blog/articles/pdf-converter-guide/): Why a Word file changes when it becomes a PDF, which settings prevent it, and how to check the pages that moved before you send the file. - [Word to PDF vs Print to PDF: What’s the Difference?](https://studykittools.com/blog/articles/word-to-pdf-vs-print-to-pdf/): Print to PDF captures what the screen shows, while Word to PDF rebuilds the document. The difference affects links, fonts, and how text behaves. - [Why Fonts Change When You Convert Word to PDF](https://studykittools.com/blog/articles/why-fonts-change-when-you-convert-word-to-pdf/): A PDF can only keep a font it can find or embed. Here is why substitution happens, how it moves the layout, and what to check before sending. - [How to Split a PDF into Separate Files or Page Ranges](https://studykittools.com/blog/articles/split-pdf-guide/): How to choose between separate files and page ranges, find the real page numbers, and check what a PDF split does to links and forms. - [How to Extract Pages from a PDF](https://studykittools.com/blog/articles/how-to-extract-pages-from-a-pdf/): Note the viewer page numbers, extract the range you need, and check the new file before sending it. A short guide to pulling pages out cleanly. - [How to Split a PDF by Chapter or File Size](https://studykittools.com/blog/articles/how-to-split-a-pdf-by-chapter-or-file-size/): Split at chapter boundaries when structure matters, and near a section break when size is the limit. Planning the ranges saves renaming later. - [How to Combine PDFs in the Right Order](https://studykittools.com/blog/articles/how-to-combine-pdfs-in-the-right-order/): Decide the reading order before you merge, number the files, and check every join. A practical method for building one PDF from several parts. - [Why Merged PDFs Get So Large](https://studykittools.com/blog/articles/why-merged-pdfs-get-so-large/): Merged PDFs grow because every file brings its own fonts, images and metadata along, and none of that is shared between documents. - [How to Reorder, Rotate, and Delete PDF Pages](https://studykittools.com/blog/articles/pdf-editor-guide/): A page-by-page method for reordering, rotating and deleting pages in a PDF, including what to check before you download the edited file. - [How to Delete Blank Pages from a PDF](https://studykittools.com/blog/articles/how-to-delete-blank-pages-from-a-pdf/): Blank pages in a PDF usually come from page breaks or scanned separators, and removing them means checking what is left behind. - [How to Rotate a Scanned PDF and Keep It Readable](https://studykittools.com/blog/articles/how-to-rotate-a-scanned-pdf/): Rotating a scanned PDF means setting the page orientation, not turning the picture, so the text stays sharp and searchable. - [PDF or EPUB? Choosing a Format for Your E-Reader](https://studykittools.com/blog/articles/pdf-to-epub-guide/): When a PDF is the right format for an e-reader, when an EPUB is better, and what conversion can and cannot preserve from a text-based PDF. - [Why PDFs Convert Badly to EPUB](https://studykittools.com/blog/articles/why-pdfs-convert-badly-to-epub/): A PDF describes where text sits on a page and an EPUB describes a flow of text, which is why converting between them loses structure. - [How to Send a PDF or EPUB to a Kindle](https://studykittools.com/blog/articles/how-to-send-a-pdf-or-epub-to-a-kindle/): Kindles accept EPUB and PDF by email or over USB, but EPUB needs to be in the right format and the sender must be approved first. - [How to Make a QR Code for a Link That Lasts](https://studykittools.com/blog/articles/url-qr-generator-guide/): How to make a QR code for a link that keeps working, why redirect services fail, and how to test a printed code before the print run. - [Static vs Dynamic QR Codes: Which Do You Need?](https://studykittools.com/blog/articles/static-vs-dynamic-qr-codes/): Static codes store the destination in the pattern; dynamic codes rely on a redirect. Compare control, cost, and long-term reliability before printing. - [Why Your QR Code Won’t Scan](https://studykittools.com/blog/articles/why-your-qr-code-wont-scan/): Most QR codes that fail to scan are too small, too glossy, or too dense. Check size, contrast, and quiet zone before generating a new code. - [What Can You Put in a Text QR Code?](https://studykittools.com/blog/articles/text-qr-generator-guide/): What a text QR code can carry, where it works better than a link, and how length and character choice affect whether it scans. - [How Much Text Fits in a QR Code?](https://studykittools.com/blog/articles/how-much-text-fits-in-a-qr-code/): QR capacity depends on version, error correction, and character set. Practical ranges for text, URLs, and labels, and why dense codes need bigger prints. - [QR Code Error Correction: Why Damaged Codes Still Scan](https://studykittools.com/blog/articles/qr-code-error-correction-explained/): Error correction lets a damaged QR code keep working, within limits. How the four levels differ and when to choose H instead of L. - [How Email QR Codes Work and When to Use One](https://studykittools.com/blog/articles/email-qr-generator-guide/): How mailto QR codes open a draft message, where they help, and why prefilled subjects and body text often break across mail apps. - [How to Make a QR Code That Opens an Email Draft](https://studykittools.com/blog/articles/how-to-make-a-qr-code-that-opens-an-email/): A mailto QR code opens a draft with the address and subject filled in. How to build one, what breaks across mail apps, and how to test it. - [QR Codes for Business Cards: What to Include](https://studykittools.com/blog/articles/qr-codes-for-business-cards/): A business card QR code should do one job well. What to encode, what to print beside it, and how to test it at actual card size. - [How a Wi-Fi QR Code Works Without Exposing the Password](https://studykittools.com/blog/articles/wifi-qr-generator-guide/): What a Wi-Fi QR code contains, why the password is recoverable from it, and how to set up guest access that is convenient and contained. - [How to Share Wi-Fi Without Typing the Password](https://studykittools.com/blog/articles/how-to-share-wifi-without-typing-the-password/): A Wi-Fi QR code carries the network name and password, so scanning joins without typing. Treat the printed code like a written password. - [Guest Wi-Fi QR Codes: Setup and Placement](https://studykittools.com/blog/articles/guest-wifi-qr-codes/): A guest Wi-Fi QR code works best on a separate network with its own password. Setup, placement, and rotation without reprinting everything. - [How to Scan a QR Code Safely Before You Open It](https://studykittools.com/blog/articles/qr-scanner-guide/): A QR code can point anywhere, so decode it first and check the address before you open it, enter details, or pay anything. - [How to Check a QR Code’s Destination Before Opening It](https://studykittools.com/blog/articles/how-to-check-a-qr-code-destination-before-opening/): Preview the decoded URL before opening a QR code. Check the domain, watch for shorteners, and treat the code as a container rather than a promise. - [QR Code Scams: What They Look Like and How to Avoid Them](https://studykittools.com/blog/articles/qr-code-scams/): QR code scams rely on urgency, fake notices, and stickers over real codes. Learn the common patterns and the checks that stop them. - [How to Calculate GPA from Credits and Grades](https://studykittools.com/blog/articles/gpa-calculator-guide/): GPA is a credit-weighted average: multiply each grade's points by its credits, add them up, and divide by the total credits. - [Weighted vs Unweighted GPA: What Is the Difference?](https://studykittools.com/blog/articles/weighted-vs-unweighted-gpa/): Why the same grades can produce two different GPAs, how course difficulty is weighted, and which number a school is likely to use. - [What Is a Good GPA?](https://studykittools.com/blog/articles/what-is-a-good-gpa/): Why there is no universal answer, how admissions and employers read a GPA, and what to do if yours is lower than you hoped. - [Percentage Increase, Decrease, and Difference Explained](https://studykittools.com/blog/articles/percentage-calculator-guide/): Percentage change uses the original value as its base, while percentage difference uses the average; mixing them gives a misleading number. - [How to Calculate a Percentage of a Total](https://studykittools.com/blog/articles/how-to-calculate-percentage-of-a-total/): The part-over-whole formula, the mistakes that produce impossible percentages, and how to check the answer in your head. - [How to Calculate Discounts, Tax, and Tips](https://studykittools.com/blog/articles/how-to-calculate-discounts-tax-and-tips/): Work out a sale price, add tax in the right order, and split a bill without losing track of the arithmetic when the bill arrives. - [How to Capture a Tab, Window, or Selected Area](https://studykittools.com/blog/articles/screenshot-capture-guide/): Choose tab, window, screen, or selected area to suit the subject, clear the frame of clutter first, and save the result as a PNG. - [How to Take a Scrolling Screenshot](https://studykittools.com/blog/articles/how-to-take-a-scrolling-screenshot/): Capture a long page in overlapping sections, stitch them into one clean image, and check the seams before you share the result. - [How to Annotate a Screenshot for a Bug Report](https://studykittools.com/blog/articles/how-to-annotate-a-screenshot-for-a-bug-report/): Crop to the evidence, mark the exact fault with a box or arrow, and add a short caption that says what you expected to happen. - [How to Record Your Screen with Audio](https://studykittools.com/blog/articles/screen-recorder-guide/): Decide whether you need narration, system audio, or both, test the microphone, and record the smallest area that tells the story. - [How to Record Your Screen with Clear Audio](https://studykittools.com/blog/articles/how-to-record-screen-with-clear-audio/): Choose the right audio source, keep the microphone close, and test the whole chain before recording a single minute of screen video. - [Why Screen Recordings Get So Large](https://studykittools.com/blog/articles/why-screen-recordings-get-so-large/): Resolution, frame rate, duration, and codec all multiply together, which is why a short screen capture can produce a surprisingly large file. - [How Automatic Video Clipping Finds the Highlights](https://studykittools.com/blog/articles/video-auto-clip-guide/): Automatic clipping finds likely highlights from changes in sound and picture, then cuts them into clips you still need to review. - [How to Turn a Long Video into Short Clips](https://studykittools.com/blog/articles/how-to-turn-a-long-video-into-short-clips/): Find the moments worth keeping, cut them with enough context to stand alone, and check every start and end before you publish. - [Why Automatic Clips Cut Mid-Sentence](https://studykittools.com/blog/articles/why-automatic-clips-cut-mid-sentence/): Automatic clipping reacts to changes in sound and picture, not to grammar, so its cut points can land inside a spoken sentence. - [How to Build a Revision Timetable That Survives Contact](https://studykittools.com/blog/articles/study-planner-guide/): How to build a revision timetable you will actually follow: weight your subjects, interleave them, and absorb a missed day without rebuilding the plan. - [How to Spread Revision Across the Weeks You Have](https://studykittools.com/blog/articles/how-to-spread-revision-across-the-weeks-you-have/): Spreading revision means each subject appears more than once with gaps between, which retains far more than finishing one subject before starting the next. - [How Many Hours a Day Should You Actually Revise](https://studykittools.com/blog/articles/how-many-hours-a-day-should-you-revise/): Sustainable revision is usually two to four focused hours a day, because attention limits what can be learned regardless of how long you sit at the desk. - [How to Take Cornell Notes Without Copying the Lecture](https://studykittools.com/blog/articles/cornell-notes-generator-guide/): How to take Cornell notes worth reviewing: write cues as questions, summarise the next day from memory, and why the format only works if you retrieve. - [What Goes in the Cue Column and the Summary Band](https://studykittools.com/blog/articles/what-goes-in-the-cue-column-and-summary-band/): The cue column holds questions that test you, not headings, and the summary band states the argument of the whole page in two or three sentences. - [Cornell Notes vs Linear Notes: Which Suits Your Subject](https://studykittools.com/blog/articles/cornell-notes-vs-linear-notes/): Cornell notes suit subjects built on arguments and relationships, while linear notes suit sequences, procedures and anything you will quote directly. - [How to Turn Your Notes into a Quiz You Can Mark](https://studykittools.com/blog/articles/quiz-generator-guide/): How to turn notes into a quiz, which separators the parser reads, how marking stays strict, and why testing yourself beats rereading by a wide margin. - [How to Write Questions That Actually Test Recall](https://studykittools.com/blog/articles/how-to-write-questions-that-test-recall/): A question tests recall only when its wording does not give away the answer, so avoid cues and single-word prompts that can be matched from the notes. - [Why Self-Testing Beats Rereading Your Notes](https://studykittools.com/blog/articles/why-self-testing-beats-rereading/): Rereading builds familiarity that feels like knowledge, while self-testing forces retrieval and shows what you actually cannot recall. - [How to Turn a Passage into Guide Sections You Can Revise From](https://studykittools.com/blog/articles/ai-study-guide-generator-guide/): What an AI study guide can and cannot do: it selects facts from your passage, it cannot select what is not there, and how to check the output before revising. - [How to Check a Generated Study Guide Before You Trust It](https://studykittools.com/blog/articles/how-to-check-a-generated-study-guide/): Check a generated guide by tracing every claim back to the source passage, because plausible additions come from general knowledge rather than the text. - [What a Check Question Should Do](https://studykittools.com/blog/articles/what-a-check-question-should-do/): A check question should require producing an explanation rather than recognising a fact, so that answering it reveals a real gap or confirms real knowledge. - [How to Make Flashcards That Actually Work](https://studykittools.com/blog/articles/flashcards-guide/): Write one focused question per card, answer it aloud before flipping, and review at increasing intervals so recall sticks. - [Leitner System vs Spaced Repetition: How to Schedule Reviews](https://studykittools.com/blog/articles/leitner-system-vs-spaced-repetition/): The Leitner system sorts cards through fixed boxes, while spaced repetition schedules each card on its own expanding interval. - [How to Write Good Flashcard Questions](https://studykittools.com/blog/articles/how-to-write-good-flashcard-questions/): A good card asks about one idea, has a specific answer, and cannot be answered correctly without actually recalling the material. - [How to Compress Audio Without Losing Quality](https://studykittools.com/blog/articles/audio-compressor-guide/): Pick the smallest bitrate that still sounds clean, compare a short sample, and keep the original before compressing the whole file. - [MP3, WAV, or AAC: Which Audio Format Should You Use?](https://studykittools.com/blog/articles/mp3-vs-wav-vs-aac/): WAV keeps every sample, MP3 trades detail for compatibility, and AAC packs similar quality into fewer bits. Match the format to the job. - [How to Compress a Podcast Episode for Upload](https://studykittools.com/blog/articles/how-to-compress-a-podcast-episode-for-upload/): Keep a lossless master, trim and balance the episode, then encode a listening copy at a bitrate that survives phone speakers and platform re-encoding. ## Site - [Tools](https://studykittools.com/tools/): The full tool directory, grouped by task. - [Blog](https://studykittools.com/blog/): The blog hub, with the Articles section and the Student Guide. - [Student Guide](https://studykittools.com/guides/): The Student Guide hub. - [About StudyKit](https://studykittools.com/about/): What StudyKit is, how the tools work, and how the site is paid for. - [Contact](https://studykittools.com/contact/): How to report a bug, suggest a tool, or ask for a correction. - [Privacy Policy](https://studykittools.com/privacy-policy/): What the tools do with inputs, and what the site logs. - [Terms](https://studykittools.com/terms/): The terms for using the free tools and educational content.