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Compress an image to any size in KB

Set the size a form or website allows and get the sharpest image that fits. Add exact pixels, centimetres and DPI when the instructions ask for them.

Target size
Dimensions

More sizes

How to compress image to KB

  1. Choose your image

    Drop a photo, scan or screenshot. You can add several at once.

  2. Set your size as the limit

    Pick a preset or type your own limit, and a minimum if the form has one.

  3. Set the dimensions if asked

    Enter the exact pixels, centimetres or inches and the DPI that the instructions give.

  4. Download

    Check the size shown next to each file, then download it, or all files as a zip.

How it reaches your size

The tool first saves your image at high quality. If that is too big, it searches for the highest quality that still fits. Only when quality alone cannot get there, or would drop so low that the picture breaks up, does it make the image smaller, because a slightly smaller image at good quality looks better than a large one full of blocks.

Websites count a kilobyte as 1,000 or 1,024 bytes, so the tool aims under the limit in both. A file it marks as 20 KB passes a 20 KB limit either way.

If a form also sets a minimum, enter it. The tool then raises the quality, and the dimensions if needed, until the file is inside the range.

What fits in each size

In our tests, a detailed photo saved as a good-quality JPG came to about 20 KB at 300 x 375 pixels, 40 KB at 400 x 500, 85 KB at 600 x 750 and 150 KB at 800 x 1000. Photos with plain backgrounds, such as passport photos, come out smaller. So if a form asks for 50 KB, a photo around 400 pixels wide will look sharp, and a 4,000 pixel phone photo has to shrink a lot.

Tips for a sharper result

Crop to what matters first, such as the face or the signature. Fewer pixels of background leave more of the file for detail.

Use the pixel size the form gives. Compressing a huge photo into a small file wastes quality on detail no one will see.

Choose JPG unless the site says otherwise. Most forms accept JPG or JPEG, and WebP files are smaller but not accepted everywhere.

Questions

Why is my file a little under the limit?

Websites count a kilobyte as 1,000 or 1,024 bytes, so the tool aims under the limit in both. A file it marks as 20 KB passes a 20 KB limit either way.

Can I make an image bigger to meet a minimum size?

Yes. Enter the minimum and the tool raises the quality first, then the dimensions. It never pads the file with empty data to fake a larger size.

What does DPI change?

DPI only tells printers how large to print the image. It does not change the pixels or the file size, but some forms check it, so set it when the instructions mention one.

Which format should I use for a form?

JPG, unless the instructions say otherwise. It is accepted almost everywhere and compresses photos well. Use the format converter if you need PNG.

Can I compress several images at once?

Yes. Add up to 30 images; each gets its own result and download, and you can download them all as one zip file.

Is my image uploaded?

No. The image is compressed by your browser on your device, and nothing is sent to uncrop.si or anyone else.

Compress an image Smaller JPG and WebP files with a quality slider. Resize an image Set exact pixel dimensions and keep the proportions. Crop an image Crop to square, 4:5, 16:9 or a custom frame. Convert image format Convert between JPG, PNG and WebP.

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