Resize a signature to 10–20 KB

Photograph your signature, drop it in, and download a clean JPG that fits the KB range your form asks for. The paper is whitened so the ink stays sharp at a tiny size. Nothing is uploaded.

Drop your signature here or tap to choose
JPG, PNG, WebP · stays on your device

Why signature limits are so small

Online application forms for recruitment exams, bank jobs and university admissions commonly ask for a scanned signature in a narrow range such as 10–20 KB or 20–50 KB, often with a preferred pixel or centimetre size. A phone photo of a signature is 2–5 MB, so it has to shrink by a factor of 100 or more, and many forms also reject files that are too small or blurred.

Two published examples (always check the current notice for your own application):

Get a clean signature image first

  1. Sign with a dark pen on plain white paper. Make it the size you normally sign.
  2. Photograph it in daylight, phone held flat, no shadow from your hand or phone.
  3. Crop close around the signature, leaving a small white border. Empty paper adds pixels but no information.

What "Whiten paper" does

Grey paper, shadows and paper texture are noise, and noise is what makes a small file look muddy. With Whiten paper on, KBSnap measures how bright the paper and the ink are, pushes the paper to pure white and darkens the ink. The signature stays crisp, and more of the 20 KB budget goes to the strokes instead of the background.

Hitting a range, not just a maximum

Most compressors only know "under X KB". Signature forms often say "between 10 and 20 KB". KBSnap aims just under the maximum, treating 1 KB as 1,000 bytes and keeping a 2% margin, and then checks the result against your minimum. If it is below, you get a clear warning instead of a file the form will bounce.

Form saysSetTip
10–20 KBMin 10, Max 20Crop tightly; Max width 300–500 px
Under 20 KBMin 0, Max 20Any size under the limit is fine
20–50 KBMin 20, Max 50Use a larger scan; leave Max width empty
140 × 60 px preferred, 10–20 KBMin 10, Max 20A clean 140 px wide JPG is only about 3 KB, below the minimum. If the size range is the hard rule, use a wider image and check the result

Also need to shrink your photo for the same form? Use the 50 KB photo guide or the main compressor.

FAQ

My form says 10–20 KB. What should I set?

Set Minimum 10 and Maximum 20 (the default here). KBSnap aims just under 20 KB and warns you if the result falls below 10 KB, which can happen when the signature image is very small.

Why is my signature below the minimum?

A tightly cropped, cleaned signature can be only a few KB even at top quality. Use a larger scan or photo, clear the Max width box, or switch off "Whiten paper" so more detail is kept. KBSnap does not add filler bytes to inflate a file.

Should the signature be black or blue?

Follow the form. Many exam and bank forms ask for black ink on white paper. "Whiten paper" turns the image greyscale, so blue ink comes out dark grey; switch it off if the form wants to see blue ink.

The form gives pixel or cm dimensions too. Does KBSnap handle that?

Crop your signature to roughly the right shape first, then set Max width to the width the form asks for. KBSnap keeps the aspect ratio and shows the width × height under the result. Very small dimensions such as 140 × 60 px usually give a file of only a few KB, so if the form also has a minimum KB, the warning will tell you to go wider.

Is my signature uploaded anywhere?

No. The cleaning and compression happen on your device in the browser. That matters for a signature, which you should not hand to random upload sites.

Related

Reduce any image to 20 KB · Photo to 50 KB · Compress to any size · All guides