About this signature resizer
Upload forms almost always set two rules for a signature: the pixel dimensions it must fit inside, and a file size it must stay under — often a much smaller one than for the photo. This takes a scanned or photographed signature and meets both. Set the width and height the form specifies, enter the size cap in KB, and download a JPG that fits. The file is read and rewritten by a worker in your browser and never uploaded, which is worth something for an image of your own signature. The original scan on your device is left untouched.
How the signature resizer works
The signature image is decoded in a browser worker and scaled to fit inside the width and height you set, keeping its proportions, so it is never stretched and never enlarged past its original size. It is then re-encoded as JPG. If you set a size cap, the encoder starts at your quality setting and steps down until the file fits, and the result reports the quality it actually used — along with a warning when that fell far enough to be visible, since a signature that has gone blocky can be rejected as unclear.
Signature Resizer examples
A 1,200 × 400 scan, fitted to 300 × 100 with a 20 KB cap
300 × 100 JPG under 20 KB, proportions kept
The same scan with a 10 KB cap
Still fits, at a lower quality — the result names the quality it had to use
A 200 × 80 scan, box set to 300 × 100
Returned at 200 × 80; it is already inside the box and is not enlarged
A cap smaller than the image can reach at those dimensions
Reported as an error, with a prompt to reduce the width and height, rather than returning an oversized file
Limitations & privacy
One JPG, PNG or WebP up to 20 MB. A size cap works between 5 KB and 10 MB and applies to JPG and WebP only. Scaling reduces but never enlarges: a scan smaller than the dimensions you set is returned as it is, because enlarging invents detail the scanner never captured. This does not crop, deskew, remove a background or clean up a grey scan — it changes dimensions and file size, nothing else. Dimensions and size limits differ between forms and change between years, so take them from the form you are filling rather than from anywhere else.
Inputs and results stay in this browser. Only tool identifiers are stored for your recently used tools. You can clear that history from the directory.
Signature Resizer: frequently asked questions
How do I resize a signature to 20 KB?
Choose the scan, set the width and height your form specifies, enter 20 in the target size field, and download. The encoder steps quality down until the file fits. Anything from 5 KB upward works the same way.
What size should my signature be?
Whatever the form says. Dimension and file-size rules differ between application portals and change between years, so the numbers printed next to the upload field are the ones to use — not a figure from a tool or a guide, including this one.
The signature looks blocky after resizing. What now?
That happens when a small size cap is reached by quality alone. Reduce the width and height first: fewer pixels reach the same file size at a much higher quality. The result warns you when quality dropped below 35% for this reason, because an unclear signature can be rejected.
Does this crop or clean up the scan?
No. It changes dimensions and file size only. Cropping away whitespace, straightening a tilted scan or whitening a grey background are separate jobs this does not do.
Will it enlarge a small scan?
No. Scaling only reduces. If your scan is already smaller than the box, it comes back unchanged — enlarging would invent detail that was never there and usually looks worse.
Is my signature uploaded anywhere?
No. A worker in your browser reads and rewrites the image on your own device. Nothing is sent to a server, which is the point for an image of your signature.
Updated October 10, 2026