✍Drop your signature image hereA photo or scan of your signature on white paper. It stays on your device.
Result
Tested in November 2026. Resizing, format change and the maximum size limit were tested with generated images. The minimum size field only gives a warning.
How to resize a signature image
- Drop a photo or scan of your signature on white paper into the box.
- Pick a common size such as 200 x 80 px, or choose Custom and enter the width and height. You can use pixels, centimetres, millimetres or inches.
- Choose how to fit: keep the shape, stretch to the exact size, or crop to fill.
- Pick the format (JPG, PNG or WebP). Enter a maximum size in KB if the form has a limit.
- Click Download signature.
Tips for better results
- Sign with a dark pen on plain white paper and take the photo in good light.
- Crop close to the signature before you upload so it stays large after resizing.
- Use Fit inside to avoid squashing the signature. Use Stretch only when the form needs an exact size.
- Choose JPG for the smallest file. Choose PNG for sharp lines.
Limits to know about
- The tool does not remove the paper background or make it transparent.
- To meet a size limit it lowers quality, so a very small limit can blur thin lines.
- The minimum file size field is only checked. The tool tells you if the file is smaller than your minimum but does not make it bigger.
- Each site has its own rules. Check the exact pixel size and format it asks for.
Privacy
Your signature image is processed inside your browser and is not uploaded. Please keep copies of your signature only where you trust them.
Frequently asked questions
What size should an online form signature be?
It depends on the form. Common sizes are 140 x 60, 200 x 80 and 256 x 64 pixels. Use the one your form states.
How do I make a signature under 20 KB?
Enter 20 in the maximum size box and download. The tool lowers quality until the file fits, if it can.
Can I use centimetres?
Yes. Pick centimetres, millimetres or inches and set the DPI so the pixel size is worked out for you.
Does it make the background transparent?
No. Use a clean white background when you take the photo.
Is it free?
Yes, with no sign-up.
About this tool
ToolsRiver Signature Resizer changes the size, format and file size of a signature image so it fits online application forms. It works in your browser.