Signature size for online forms: KB, cm and pixels

The signature size for most Indian online forms is a small, wide JPG of about 10 to 30 KB. SSC wants 10 to 20 KB at about 6 x 2 cm, PAN under 10 KB at 2 x 4.5 cm, NEET 4 to 30 KB, and UPSC 20 to 100 KB. Check the current notice for your exam.

Most rejections come from two things: a file outside the KB range, or a signature photo that is too dark, tilted or cropped badly. Below are the verified specs, the pixel maths, and the steps to make a signature that passes the first time.

Signature size by exam and form

These are the figures from the 2026 notices and official scan specs. Rules can change between cycles, so treat this as a starting point and confirm against the notice for your exam.

• SSC: JPG or JPEG, 10 KB to 20 KB, about 6.0 cm wide x 2.0 cm high. No fixed pixel size is published. The SSC photo and signature guide has the full rules, including the live photo capture.
• PAN card (Protean online application): signature 2 x 4.5 cm (height x width), 200 DPI, colour, JPEG, maximum 10 KB. That works out to about 354 x 157 pixels. See the PAN card photo size guide for the matching photo spec.
• NEET UG: signature 4 KB to 30 KB, JPG, in black pen on white paper. The NEET photo size guide covers the passport photo, postcard photo and thumb impression too.
• UPSC: sign three times, one below the other, on white paper in black ink, and scan the three as one JPG of 20 KB to 100 KB and 350 to 500 pixels. Details are in the UPSC photo size guide.

Other recruitment boards, banks and universities set their own limits. If a notice gives pixels, use them. If it gives only KB and cm, use the method below.

10 KB to 20 KB signature size in pixels

There is no single official pixel size for a 10 to 20 KB signature unless your notice states one. KB measures file size, and pixels measure dimensions. The same signature can be 8 KB or 40 KB at identical pixel dimensions, depending on JPG quality and how clean the paper looks.

When the form gives a size in cm, convert it with pixels = cm / 2.54 x DPI:

• 6 x 2 cm at 200 DPI: about 472 x 157 pixels.
• 6 x 2 cm at 300 DPI: about 709 x 236 pixels.
• 4.5 x 2 cm at 200 DPI: about 354 x 157 pixels (the PAN signature).

At those sizes, JPG quality decides where the file lands, so expect to adjust it once or twice. If it comes out under 10 KB, raise the quality or use the 300 DPI size. If it's over 20 KB, lower the quality a little or clean up the grey background, which is what eats most of the bytes.

How to prepare a signature that scans cleanly

1. Sign on plain white paper with a black pen (or the ink colour the notice asks for). A gel or felt pen gives a darker line than a ballpoint.
2. Sign a little larger than normal so the strokes stay readable after shrinking.
3. Photograph it straight from above in daylight, with no shadow from your phone or hand. A scanner is even better.
4. Crop tightly around the signature, leaving a thin white margin on every side. The Crop Image tool lets you drag a free frame or fix a ratio.
5. Convert to black and white and raise the contrast so the paper turns white. This removes grey tones and shrinks the file. Skip this step if the notice asks for a colour scan, as PAN does.

For UPSC, sign three times before you scan, then crop all three as one image.

Signature resize in KB, step by step

Do the steps in this order. Changing the dimensions after compressing changes the KB size again.

1. Open Resize Image and add the cropped signature.
2. Choose cm and enter the size from the notice, such as 6 x 2, with a DPI of 200. Or choose pixels if the notice lists them.
3. Use Exact (cover) mode only if your crop already matches the shape. Otherwise crop to the right ratio first so the strokes aren't stretched.
4. Set the maximum file size, for example 19 KB for a 20 KB limit, and download the JPG.
5. Check the size in KB and open the image at full size. Every stroke should be clear.

If you only need to hit a KB target and the dimensions don't matter, the resize image to 20KB page does it in one step. It lowers quality first and shrinks dimensions only if it has to.

How to make a signature image on your phone

You don't need a scanner or a computer. A phone camera and a browser are enough for any of the forms above.

1. Put the signed paper on a flat table near a window, and turn off the flash to avoid a bright spot.
2. Hold the phone straight above the paper so the signature isn't skewed, and fill most of the frame with it.
3. Crop and rotate it in your phone's photo editor, or in a browser crop tool, until the line of the signature is level.
4. Open a resize tool in the phone's browser, set the cm or pixel size and the KB limit, and download the JPG.
5. Upload the downloaded file from your Files or Downloads folder, not from a chat app that may compress it again.

On an iPhone, the camera may save photos as HEIC. Convert the photo to JPG with a HEIC converter before resizing, and check that the final file really ends in .jpg.

20 KB signature size: maximum or minimum?

Read the limit carefully, because "20 KB" means different things on different forms. For SSC, 20 KB is the ceiling and 10 KB the floor. For UPSC, 20 KB is the floor and 100 KB the ceiling. For PAN, the whole file must stay under 10 KB.

• Over the maximum: lower the JPG quality, reduce the pixels slightly, or whiten the background.
• Under the minimum: raise the quality or use more pixels, such as the 300 DPI size. Don't pad the image with a big white border, because that changes the shape and can break a pixel rule.
• Close to the edge: stay a little inside the range. Some systems count 1 KB as 1,000 bytes and others as 1,024.

Why a signature upload gets rejected

• The file is outside the KB range, often just over the limit or under a minimum.
• The file is a PNG, PDF or HEIC when the form wants JPG. Convert it; renaming doesn't work.
• The scan is dark grey, blurry, tilted or cut off at the edges.
• The signature fills too little of the frame because the crop left a wide margin.
• The photo was uploaded in the signature field, or the other way around.
• For UPSC, the image has one signature instead of three.

Keep the original photo of your signature. If a later form has different limits, you can resize from that clean copy instead of squeezing an already compressed file.

Frequently asked questions