Resize signature for online forms
Turn a photo of your signature into the exact pixel size and KB limit your form needs.
- Free, no sign-up
- Files never uploaded
- No watermark
- No limits
Your photo is processed in your browser and is never uploaded.
How to compress an image to signature
- Tap Choose a photo and pick an image from your phone or computer.
- Check the target size and pixel dimensions. Change them if your form needs something different.
- Tap Download JPG and upload the file to your form.
Signature requirements on online forms
Exam, job and government forms usually ask for a signature image with fixed dimensions and a small file size, often 10 to 20 KB. This tool is set to 140 × 60 pixels and under 20 KB. Change the numbers above if your form asks for something different.
How to photograph your signature
- Sign with a black or dark blue pen on plain white paper.
- Take a photo straight from above in good light, without shadows.
- Crop the photo close around the signature in your phone's gallery.
- Choose it above and download the resized file.
The image is cropped from the centre to fit the exact size, so leave only a little space around your signature.
Frequently asked questions
What size should a signature be for an online form?
It depends on the form, so check its instructions. A common requirement is 140 × 60 pixels and 10 to 20 KB, which is what this tool is set to.
The form says my signature file is too small. What do I do?
A 140 × 60 signature is naturally only a few KB. Keep 10 in the Min size box and DocSlim makes the file at least 10 KB without changing how the signature looks.
My form asks for the size in centimetres. What do I enter?
Multiply centimetres by 118 to get pixels at 300 DPI. For example, 4 cm × 2 cm is about 472 × 236 pixels.
Is my photo uploaded to a server?
No. The compression runs inside your browser on your own device. Your photo is never uploaded, stored or seen by anyone.
Is this tool free?
Yes. It's completely free, with no sign-up, no watermark and no limit on how many images you compress.
Why is the result a little under the limit instead of exactly the limit?
Forms reject files that are even one byte over. DocSlim counts 1 KB as 1,000 bytes and aims just below your limit, so the file passes whether the website counts 1 KB as 1,000 or 1,024 bytes.