Compress Image to 20 KB

What actually fits in 20 KB

Start with arithmetic, because it explains everything else on this page. A JPEG photograph at moderate quality costs about 1.8 bits per pixel, so 20 KB buys a budget of roughly 93,000 pixels — roughly 350 × 260 pixels of photograph — noticeably more if the image is a signature or drawing on a plain background. Around 350 × 260 is the honest shape of that budget for a 4:3 photo.

Printed, 20 KB stretches to about three centimetres before the softness shows. It is enough for an on-form thumbnail and nothing more.

Those figures assume photographic content. Plain-background material — a signature, a form, a diagram — beats the 350 × 260 estimate handily at 20 KB, while dense textures like foliage or fabric undershoot it.

Where the 20 KB limit comes from

This page exists because upload forms reject files, and they reject them at round numbers. The situations that bring people here: a passport-style photo for an exam application, a signature scan that a portal caps at 20 KB, or a profile image for a bandwidth-starved service.

The 20 KB cap is the classic exam-form limit: photo and signature uploads on many recruitment and admission portals sit at or near this number.

However the 20 KB cap reached you, the problem has one shape: the file is bigger than the form will take, the error message is unhelpful, and guessing at export settings burns a submission attempt per guess. Naming 20 KB as a target and letting the tool search for it is the mechanism the job actually calls for.

How this tool reaches 20 KB exactly

Under the hood this page runs a binary search for 20 KB: the image is encoded at a mid quality, the result is measured, and the search range halves each round. Eight rounds pin the best fitting quality to within a point, at well under a second per image, all in local memory.

Quality alone rarely gets a camera image under 20 KB: a 4,000 × 3,000 phone photo overshoots the 93,000-pixel budget even at the quality floor, so the tool rescales it — to roughly 352 × 264 in that case, estimated from how far over the attempt landed — and searches again. The result line shows the final dimensions, so the trade is never silent.

Leave the output format on JPG if a portal set the 20 KB cap: forms that check size usually check type too, and they expect JPEG. WebP would fit 20 KB at visibly better quality, but only choose it when the destination is a site you control.

Because files at 20 KB caps are so often signatures, ID photos and documents: nothing here leaves your device. Decoding, rescaling, the quality search and the final encode all run inside this browser tab — there is no upload and no server-side copy.

Getting the best result at 20 KB

The most valuable 20 KB trick is done before this page: crop hard. Wasting the 93,000-pixel budget on the empty paper around a signature or the wall behind a face is what makes tiny targets look bad; a tight crop redirects every byte to the subject.

Light and contrast beat megapixels at this size. Dark pen on plain white paper, photographed in daylight without shadows, compresses dramatically better than faint pencil on ruled paper — if a portal rejects your 20 KB file on legibility rather than size, re-shoot the original instead of fighting the encoder.

Portals that cap size at 20 KB often cap dimensions too. When yours does, resize to the demanded width and height first, then compress here — in that order the encoder is not fighting excess pixels, and more of the 20 KB goes to quality.

Because photo and signature usually travel together on the same form, do them in one visit: compress the photo here, then open the 10 KB page linked below for the signature. The two caps differ for a reason — a signature is line art and needs far fewer bytes than a face.