Why is my signature rejected for being too small when it is under 20 KB?

Many forms ask for a size window, for example 10 KB to 20 KB, and reject a file below the minimum as firmly as one above the maximum. A clean 140 x 60 signature compresses to around 3 KB, and even at the highest quality setting it does not pass about 5 KB. Raising the quality cannot reach 10 KB. The file has to be padded with blank filler that image viewers skip, which leaves the picture unchanged.

What size is a signature for SSC and IBPS forms?

140 x 60 pixels at 10 KB to 20 KB is the size people most often report for SSC, IBPS and many state recruitment portals. Requirements change, so always use the numbers printed in your own notification.

How to Get Your Signature Under 20 KB for an Online Application Form

Q: How do I reduce my signature to under 20 KB?

Resize it to the exact pixel dimensions your form asks for, such as 140 x 60, and save it as a JPG. At that size a clean signature on white is only a few KB, so it is almost always under 20 KB once the dimensions are right. If it is still too big, lower the JPG quality.

Q: Should I stretch my signature to fit 140 x 60 pixels?

No. Stretching distorts your handwriting. Scale the signature to fit inside the box and fill the leftover space with white, so it keeps its proportions.

Most people fix the maximum size and still get rejected. The minimum size is the part that catches them out, and no quality setting will fix it.

In a hurry? The Signature Extractor takes a phone photo of your signature and gives you a JPG at the exact pixels and KB range your form asks for. It is free and needs no signup. The rest of this page explains what the form is checking, so you know why a file gets rejected.

What the form is actually checking

A typical instruction reads something like this: signature, 140 x 60 pixels, 10 KB to 20 KB, JPG format. That is three separate checks, and the portal runs all of them:

Pixel dimensions - the width and height of the image, for example 140 x 60. Not centimetres, not inches, and not "roughly".
Maximum file size - the upper limit, for example 20 KB.
Minimum file size - the lower limit, for example 10 KB. Not every form has one, but many recruitment and exam portals do.

Some notifications also say black ink, white background, or JPG only. Read yours carefully and write the numbers down before you start. The size people most often report for SSC, IBPS and many state portals is 140 x 60 pixels at 10 KB to 20 KB, but portals change their rules, and the numbers in your own notification always win.

Step 1: take a photo that is easy to clean

Everything after this step is easier with a good photo. It takes thirty seconds.

Sign plain, unruled white paper. Ruled lines count as ink to any tool, and they come out along with your signature.
Use a dark pen with a wet line. A gel or ink pen is better than a dry ballpoint, and both are better than a pencil.
Photograph it in daylight near a window, but not in direct sun. Do not use the flash.
Hold the phone straight over the page, not at an angle, and leave some blank paper around the signature.

Your photo will still have a grey cast and probably a shadow across one side. That is normal. The next step deals with it.

The example on this page is a little harder than a phone photo. It is a signature printed in a book from 1920, scanned from the page. The paper is grey, the light is uneven, and faint print from the other side of the page shows through.

A handwritten signature on grey, uneven paper, with faint printed text showing through from the other side of the page — The starting point. Signature of Léonce de Larmandie, from Walch, volume 2 (1920). Public domain, via Wikimedia Commons.

Step 2: get the pixels exact, without stretching

A phone photo is thousands of pixels wide. The form wants 140. So the signature has to be cleaned, cropped close, and scaled down.

The mistake here is stretching. Your signature is whatever shape you wrote it, and 140 x 60 is a fixed shape. If you force one into the other, your handwriting gets squashed or pulled, and a signature that does not match the one on your other documents is a real problem later. The right way is to scale the signature to fit inside the box and fill the leftover space with white.

The same signature as clean black ink on a white square, 350 by 350 pixels — The same signature fitted into a 350 x 350 box, shown here at its real size. It is a little wider than it is tall, so a strip of white was added above and below instead of stretching it. The grey paper and the print from the other side are gone.

The other mistake is brightening the photo to make the paper white. Brightness and contrast change every pixel by the same amount, so the shadowed side of the page turns into a grey or black patch while the thin strokes on the bright side fade away. A tool built for signatures measures the paper brightness across the whole page first and removes it, so only the ink is left.

Step 3: stay under the maximum

This is the step everyone worries about, and it is usually the easiest. Once the image really is 140 x 60 pixels of black ink on white, it is tiny. A clean signature at that size comes out at around 3 KB as a JPG, far below a 20 KB limit.

If your file is over the limit, the dimensions are almost always the reason. A file that is still 50 KB or 200 KB has not really been resized, or it was saved as PNG, or it still contains the whole photo around the signature. Fix the pixels first, then check the size again.

Step 4: the minimum size, and why it catches people out

Here is where most people get stuck. They have a perfect 140 x 60 signature at 3 KB, the form says 10 KB to 20 KB, and it is rejected. The file is too small.

The natural thing is to raise the JPG quality. It does not work. At 140 x 60 there are only 8,400 pixels, and a signature is mostly plain white. Even at the highest quality setting, with nothing thrown away, the file does not pass about 5 KB. There is simply not enough picture to fill 10 KB.

The usual workarounds all break something else:

Saving at a larger size, such as 400 x 170, gets you past 10 KB but fails the pixel check.
Adding a grey or textured background makes the file bigger but breaks the "white background" rule, and the reviewer sees a dirty signature.
Adding noise does the same thing and looks worse.

The clean fix is to add filler inside the file without touching the picture. A JPG file can carry comment sections that every image viewer skips over. Filling one with blank bytes brings the file up to the minimum, while the signature itself stays pixel for pixel the same. The portal sees a 10 KB file at 140 x 60 pixels, and the reviewer sees your signature on white.

The 350 x 350 example above shows this in practice. The square preset asks for at least 20 KB. Even at the tool's highest quality setting, the signature came out at 14.5 KB, so 5.5 KB of filler was added. The file you see is exactly 20 KB, and the picture is the same as it was at 14.5 KB.

A quick checklist before you upload

The dimensions match your notification exactly, for example 140 x 60.
The file size is inside the window, above the minimum as well as below the maximum.
The file is a JPG, if the form asks for JPG. Renaming a PNG to .jpg does not make it a JPG.
The ink is dark and unbroken, and the background is white with no grey patch or shadow.
The signature is not stretched or squashed.
You uploaded it in the signature box, not the photo box. It happens more often than you would think.

Doing it with Fix Shots

I built the Signature Extractor for exactly this job, because the minimum size problem had no simple answer in the tools I tried.

Open the Signature Extractor and upload the photo of your signature.
Keep Filling in a form selected.
Click the 140 x 60 preset, or type the width, height, minimum KB and maximum KB from your own notification.
Click Extract Signature, check the preview, and download.

It removes the paper and the shadow, crops to the signature, fits it inside the box without stretching, keeps it under the maximum, and adds filler only if the minimum needs it. When it adds filler, it tells you so. If your strokes come out broken, raise the ink strength slider. If specks of paper texture show through, lower it.

If you need a signature for a contract or a PDF instead of a form, choose Signing a document. You get a transparent PNG with no white box around the ink, in the ink colour you pick.

The same signature in teal ink on a transparent background, shown over a light checkerboard — The same signature from the document option, as a transparent PNG in teal ink. The checkerboard is only there so you can see the transparency. The small mark near the middle is in the original scan as well. It was big enough to be kept as ink.

Most forms ask for a photo as well as a signature. For that, use Compress to Exact Size, or go straight to the 20 KB or 50 KB page. Photos need a different approach from signatures, because a face must keep its grey tones.

Is my signature kept anywhere?

No. Your image is uploaded to the server only while it is being processed. It is not saved, logged or kept, and it is discarded as soon as your result is sent back to you. There is no account to create.

Frequently asked questions

How do I reduce my signature to under 20 KB?

Resize it to the exact pixel dimensions your form asks for and save it as a JPG. At 140 x 60 a clean signature is only a few KB, so getting the dimensions right almost always solves the size as well.

Why is my signature rejected when it is under 20 KB?

Your form probably has a minimum as well, such as 10 KB. A small, clean signature falls below it, and raising the quality cannot fix that. The file needs blank filler added inside it, which leaves the picture unchanged.

Can I sign on my phone screen instead of paper?

You can, but a finger on glass rarely looks like your pen signature, and many forms want it to match what you sign on paper. Signing on paper and photographing it is the safer choice.

My notification gives the size in centimetres, not pixels. What do I do?

Look again for a pixel size in the same section, because most portals give one. If there really is none, contact the body that issued the notification rather than guessing, because the pixel size depends on a resolution they have not told you.