Signatures for digital forms
Compress Signature to 20 KB
Preset and ready: drop a file and the output lands under 20 KB as JPEG — processed entirely in your browser.
Drop your image here or browse
JPEG, PNG, WebP — iPhone HEIC tips inside — processed entirely in your browser
Why this exact limit matters
Scanned signatures are awkward files: a black-on-white scan from a phone produces an image that is far larger than the tiny limits forms allow, yet the signature itself has almost no visual complexity. Size limits that look brutal for photos are usually easy for signatures.
A signature is high-contrast line art, which compresses extremely well — hitting a small kilobyte target normally costs almost nothing in legibility. 20 KB is one of the tightest limits you will meet online, and this page is preset to exactly that ceiling.
How to compress to 20 KB
- Drop your signature scan into the box above — it stays on your device.
- Confirm the target: under 20 KB as JPEG.
- The MozJPEG encoder searches its quality range so the JPEG output lands just under your limit. Dimensions are left at their original size unless the target demands otherwise.
- Preview the result, compare it with the original if you want, and download — the filename carries its actual size.
Tip: If your scan has a grey or shaded background, the encoder spends bytes on that noise. A clean white background is the single biggest size saver for signature files.
Frequently asked questions
How do I scan my signature in the first place?
Sign on plain white paper, photograph it in even daylight, crop tightly around the signature, and bring it here. Crop first — everything that is not signature is wasted bytes.
How does the tool hit the exact JPEG size?
It encodes your image with the MozJPEG encoder several times, binary-searching the quality setting until the output lands just under your limit — then keeps that best result.
What happens to my image when I close the tab?
It is discarded from memory. Nothing was transmitted and nothing was stored, so there is nothing to delete.