Compress image to 20 KB
Make a photo or a scanned signature fit under 20 KB. The limit is already set: choose the picture and press Compress.
This free online tool to compress an image to 20 KB runs in your browser, with nothing to install and no account. Add several photos to bring each one under 20 KB in one go. How the files you choose are handled is set out in the privacy policy.
How to compress an image to 20 KB
- Tap Choose pictures and select the photo. You can select several.
- A size limit is already chosen, with 20 in the box. Change the number if your form asks for something else.
- Press Compress. The result shows the size before and after.
- Press Save picture. The original file is not changed.
Each picture is saved as a JPG at the best quality that fits under 20 KB. The limit is counted with 1,024 bytes to the KB, as Windows and nearly all upload forms count, so 20 KB allows up to 20,480 bytes.
The line under the result rounds in units of 1,000 bytes, so a file close to the limit can read a little higher there than it does in Windows. If a form still refuses the file, type a slightly smaller number, such as 19, and compress again.
What fits in 20 KB
Twenty kilobytes is very little: about one two-hundredth of a photo straight from a phone camera. A picture has to be small in pixels to look good at that size.
| Picture | Size in pixels that looks good under 20 KB |
|---|---|
| A signature on white paper | Up to about 600 pixels wide |
| A passport-style face photo | About 200 to 300 pixels wide |
| A detailed photo, such as a landscape | About 200 pixels wide |
You do not have to work that out yourself. If the picture is still over 20 KB at the lowest acceptable quality, it is made smaller in pixels until it fits, and the result tells you the new size.
Signatures for online forms
Exam, recruitment and admission forms usually ask for a scanned signature with a small limit, commonly 10 to 20 KB, alongside a photo with a slightly larger one.
- Sign in dark ink on plain white paper, larger than you normally would.
- Photograph it in even light, straight from above, with no shadow across the paper.
- Cut away the empty paper with crop image, leaving a narrow margin. Blank paper costs kilobytes too.
- Then compress the cropped picture here.
A signature is plain dark lines on a white ground, so it compresses very well and stays sharp far below 20 KB.
When the form also sets a size in pixels
Many forms give two rules, for example 140 × 60 pixels and under 20 KB for a signature, or 200 × 230 pixels and 20 to 50 KB for a photo. Do the pixels first: set the exact width and height with resize image, then bring the result here.
If the form also states a minimum, such as “between 10 and 20 KB”, and your result is under it, the picture has too few pixels or too little detail to need the space. Resize it a little larger and compress again.
If the result looks rough
Blocky edges and smeared detail mean too many pixels are being squeezed into too few bytes. Crop tighter, so that the 20 KB is spent on the part that matters, or accept a smaller picture. For a face photo with a larger allowance, use compress image to 50 KB.
Questions
How do I reduce a photo to 20 KB?
Choose the photo and press Compress. The limit of 20 KB is already filled in. The picture is saved as a JPG at the best quality that fits.
How do I resize a signature to 20 KB?
Photograph the signature, crop away the empty paper, then compress it here. If the form asks for exact dimensions, set them with resize image before compressing.
Will the picture be exactly 20 KB?
It will be at or just under 20 KB, never over. Forms set a maximum, so slightly under is what you want.
Can I compress to 10 KB or 15 KB instead?
Yes. Type the number you need in the box. The smallest limit the tool accepts is 5 KB.
Why did the picture get smaller in pixels?
Because at its original size it could not fit in 20 KB even at the lowest acceptable quality. The result says what size it was reduced to.