What a Photo Actually Weighs at Every KB Limit

Application forms state limits in kilobytes — 20 KB, 50 KB, under 30 KB — but almost nothing tells you what a photograph actually weighs once compressed. So people guess, compress, check, and guess again.

This page is the measurement. Every figure below came from running our own compressor and recording the result. If you write about exam or job-application photo requirements, these numbers are yours to cite.

The single most useful finding: dimensions set a ceiling

A JPEG cannot be made arbitrarily large by raising quality. At maximum quality, an image of a given pixel size reaches a ceiling and stops. This is why a form demanding "under 70 KB" may be setting a limit your photo cannot reach, no matter what you do.

The consequence is worth stating plainly: a 413×531 px passport photo tops out around 51 KB. If your form allows 60, 70 or 80 KB, you are already under it before you start. There is nothing to fix. A great many people spend an evening on a problem they do not have.

The reverse trap is more damaging. If a form demands a minimum of 60 KB and you submit a 413×531 px photo, it will be rejected for being too small — and no amount of compressing will help, because compression only makes files smaller. You need larger dimensions, not different quality.

Measured results at every common target

Each row names the source image it was measured on. That matters: a file's size depends on its pixel dimensions and on what the picture contains, so a single flat table covering every target from one photo would be impossible. A signature and a full-resolution portrait are different measurements and are labelled as such.

Reading the table: where the result sits just under the target, the limit was reachable and quality was tuned to meet it. Where the result is far below, the ceiling was hit first — the source image simply cannot produce a larger file at those dimensions.

Method

Every figure was produced by the compressor on this site, which works as follows:

1. Encode. The image is drawn to an HTML canvas over a white matte and encoded as JPEG at a given quality, using the browser's native canvas.toBlob().
2. Binary search. JPEG file size rises monotonically with quality, so the tool runs nine bisection steps between quality 0.05 and 0.95 to find the highest quality whose output stays under the target.
3. Reduce dimensions only if required. If even the lowest quality overshoots the target, the tool scales the image down by 15% and searches again, repeating up to sixteen times.

The quality cap of 0.95 is what produces the ceiling described above: the largest file the tool will generate at a given pixel size is that image encoded at quality 0.95.

One honest caveat. JPEG compression is content-dependent. A photograph with a plain background and soft lighting compresses smaller than one with fine texture, patterned clothing or a busy background — sometimes by 30% or more. The figures here are from real photographs of the stated dimensions and are representative, not universal. Your own photo at 413×531 px might ceiling at 45 KB or at 65 KB. What does not vary is the shape of the behaviour: a ceiling exists, and targets above it are unreachable.

The measurement harness is in the site's repository at src/measure/measure.js so the numbers can be reproduced against any image.

Photo and signature specifications by exam

The limits these measurements are set against, with the page for each:

India

• SSC — photo 20–50 KB at 413×531 px, signature 10–20 KB at 6×2 cm
• UPSC — photo 20–300 KB at 350×350 px, signature 20–100 KB
• IBPS / SBI — photo 20–50 KB at 200×230 px, signature 10–20 KB at 140×60 px
• NEET — photo 10–200 KB, 4×6 inch, signature 4–30 KB
• JEE Main — photo 10–200 KB at 413×531 px, signature 10–100 KB at 413×177 px
• RRB Group D — photo 50–100 KB at 320×240 px, signature 30–55 KB at 140×60 px
• PAN card — photo max 20 KB, signature max 10 KB

Pakistan

• PPSC — picture 10–40 KB at 140×177 px, signature 10–40 KB at 140×80 px
• FPSC — photo under 30 KB
• NTS — photo 50–200 KB
• Passport — 35×45 mm (413×531 px), white background

Provincial commissions are different. SPSC, KPPSC, BPSC and AJK PSC publish photo requirements per advertisement rather than as a standing rule, so no fixed KB figure should be quoted for them. Read the limit printed on your own advertisement and set that as the target. Our Pakistan PSC page handles any value.

Citing this page

These measurements are free to quote, with attribution. A link to this page is appreciated and lets your readers check the method.

Suggested form:

"A 413×531 px passport photograph reaches roughly 51 KB at maximum JPEG quality, so form limits above that figure cannot be exceeded." — imageto10kb, Photo File Size Reference

If you spot a figure you believe is wrong, tell us via the contact page — we would rather correct it than have it repeated.

Compress to a specific size

The tool that produced these figures is free, needs no sign-up, and runs entirely in your browser — nothing is uploaded. Set a target in KB, or a minimum and maximum for forms that specify a range.

Compress an image to an exact size →