StudyKit browser utility

Image Aspect Ratio Converter

Turn a photo into a square, a portrait, or a widescreen banner, choosing whether to crop what does not fit or pad it out.

1. Choose an image

Handled entirely in this page. Nothing is uploaded.

Choose an image, or drop one here You can also paste an image with Ctrl or Command and V JPG, PNG, or WebP

Choose an image to begin. Nothing is uploaded.

2. Result

The converted image will appear here.

Cropping is not reversible here. When you choose to crop, the preview shows exactly what will be kept, centred. If the subject is near an edge, pad instead and place the background yourself, or crop in a photo editor first and convert afterwards.

Which ratio to choose

1:1 and 4:5

Squares and portraits for feeds. 4:5 uses more of a phone screen than a square and is rarely cropped.

16:9 and 9:16

Widescreen video and its vertical form. Use 9:16 for stories, reels, and shorts.

3:2, 4:3, 21:9

Camera and display shapes. 3:2 is what most photos start as, and 21:9 makes a very wide banner.

Crop and pad are different promises

Reshaping a picture to a new ratio has two honest answers, and which one you want depends on what the picture contains. This tool offers both as separate choices rather than picking for you, because they fail in opposite directions.

Padding adds bars, and keeps everything

Padding fits the whole picture inside the new shape and fills the remainder with a colour you choose. Nothing is lost, which makes it the safe choice for a screenshot or a document. It also means a 4:3 photograph padded to 16:9 arrives with visible bars, and most platforms will crop those bars off again before anyone sees it, at which point you have gained nothing.

Cropping removes the edges

Cropping fills the new shape and discards whatever falls outside it. That is what you want for a photograph with a single subject, and it is dangerous in a specific way: the crop is taken from the centre, so the edges of the picture are the first thing to go. A group photo cropped to 1:1 can lose the people at the sides. A portrait cropped to 16:9 loses the top of the head. Check the result before you use it.

DPI is not resolution

DPI is a number stored in the file that describes an intended print size. What the picture actually contains is pixels. For print at 300 DPI, a 3480 by 2400 pixel image gives you roughly A4, and nothing more. Changing the DPI number changes no pixels and changes no detail.

Resizing up adds nothing

Enlarging an image interpolates the pixels you already have. The file gets bigger and the extra size is smoothness, not detail. If a job needs more pixels, it needs a larger original.

One pass, in a sensible order

Reshape first, then size, then compress. Doing it the other way round means compressing detail you are about to crop away, and taking the quality hit twice.