Compress JPEG to 100 KB
Compress a JPEG file to under 100 KB, keeping JPEG as the output format.
Finding the best quality that fits…
- Original
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- Result
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- Reduction
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- Dimensions
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How to use this tool
- Choose your image, drag it onto the box, or paste it from the clipboard. JPG, PNG, WebP and HEIC all go in; JPEG comes out.
- There is nothing to set. This page is already fixed at under 100.0 KB, JPEG.
- It scales the image down first — on our reference file, to 1131 × 1508 px — then searches the encoder quality. That run took 7 encodes.
- Download from the panel, which shows the original size, the final size and the output dimensions. Nothing was uploaded at any point.
JPEG is the right format for photographs and reaches small sizes efficiently. The tool searches quality levels to land just under 100 KB.
Compress JPEG to 100 KB — the specification
| Target file size | Under 100 KB |
|---|---|
| Output format | JPEG |
| Method | Binary search over JPEG quality |
| Transparency | Flattened onto white |
Compress JPEG to 100 KB: why uploads get rejected
Landing under 100 KB is necessary but not sufficient. These are the reasons a file that meets the size still gets sent back:
- The source was a PNG screenshot converted to JPEG — text and sharp edges pick up visible artefacts. For screenshots, keep PNG.
- The image was already heavily compressed, so re-compressing degrades it further.
- The dimensions are large enough that 100 KB forces heavy quality loss. Reduce the dimensions first.
How it works
Hitting a size limit exactly is a search problem, not a setting. There is no quality value that means “100.0 KB” — how many bytes a given quality produces depends entirely on the picture. So this tool encodes, measures the real file, and adjusts.
It starts by capping the pixel count, because quality alone cannot rescue an image that is simply too large. On the reference file measured below that meant going from 2448 × 3264 to 1131 × 1508 before the first encode. That ordering is what keeps the search cheap: the six or seven encodes that follow all work on the smaller image.
It then binary-searches the quality parameter: encode, measure, halve the remaining range, repeat. The run below took 7 encodes to land at 96.7 KB. A tool that picks one fixed quality instead either overshoots the limit or comes in far under it and throws away detail you did not need to lose.
Every one of those encodes ran on your own device through the browser’s canvas API — including the intermediate attempts the search threw away. None of them was uploaded.
A measured run of this exact preset
Not an estimate: this page’s own code, run against an 8 MP photograph and an A4 scan at 200 dpi, with every encode recorded. The files and the method are published here.
| Input | Result | Change | Outcome |
|---|---|---|---|
| 8 MP photograph 2448 × 3264 px · 1.88 MB | 96.7 KB 1131 × 1508 px | 95% smaller | Under the 100 KB limit |
| A4 scan at 200 dpi 1654 × 2339 px · 996.0 KB | 99.8 KB 1099 × 1554 px | 90% smaller | Under the 100 KB limit |
Step by step
Before touching quality at all, the tool worked out how many pixels 100.0 KB can realistically describe, and scaled the image from 2448 × 3264 down to 1131 × 1508 — 79% fewer pixels. Doing this first is what keeps the run quick: every attempt after it encodes the smaller image rather than the original.
The first probe at quality 0.96 came out at 450.5 KB, about 4.5× the 100.0 KB limit, so the search began.
It then narrowed the quality setting 6 times — quality 0.51 gave 69.7 KB, quality 0.73 gave 120.3 KB, quality 0.62 gave 86.6 KB, quality 0.68 gave 100.6 KB, and so on — settling on quality 0.66.
Final file: 96.7 KB, using 96.7% of the allowance, with 3.3 KB to spare.
Who needs Compress JPEG to 100 KB
Situations where the output format is fixed — a form that accepts only JPEG, or a workflow where the format must not change.
Compress JPEG to 100 KB — frequently asked questions
Why keep JPEG rather than convert?
JPEG is the most widely accepted format on upload forms and the most efficient for photographs. Keeping the format avoids compatibility surprises.
How does the quality search work?
It encodes at a mid-range quality, measures the file, and narrows the range seven times, keeping the largest result under 100 KB.
Will the file still be under 100 KB after I save it again?
Yes, as long as you do not re-encode it. Downloading and uploading the same file changes nothing. Opening it in an editor and saving again re-compresses it and can push the size back up, so upload the file you downloaded here rather than a copy you have edited.
Which file types can I upload?
JPG, PNG, WebP, GIF, BMP and HEIC from an iPhone all go in. The output here is JPEG. Conversion happens as part of the process, so there is no need to convert first.
Does this work on a phone?
Yes, including photos straight from your camera roll. The work happens on the device, so a very large image is slower on a phone than on a laptop, but nothing is uploaded either way.
Is this tool really free?
Yes. No account, no trial period, no watermark on the output and no cap on how many times you use it. The site is funded by advertising.
Is 100 KB the right target, and what you actually get
Where this limit comes from: Passport and visa photographs, PAN card applications and many document portals.
At 100 KB the image keeps 46% of its original width, with most of the reduction coming from the quality setting rather than from scaling. That is usually the sweet spot: small enough to pass, large enough to still look like the original.
The same source file put through this target and the ones either side of it, measured rather than estimated:
| Target | Result | Final size in pixels | Scaling applied |
|---|---|---|---|
| 50 KB | 49 KB | 1067 × 800 px | 27% of original width |
| 100 KB (this page) | 97 KB | 1131 × 1508 px | 46% of original width |
| 200 KB | 197 KB | 1600 × 2133 px | 65% of original width |
If the portal gives a range rather than a hard number, take the largest it allows. Every step down this ladder costs detail that cannot be recovered afterwards.
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Background reading: Image Size Requirements for Every Major Platform
Your photo never leaves your device. Open your browser's Network tab while you use this page and you will see no upload — how that works.
Disclaimer. Published requirements change without notice. Confirm against the official source before you submit. Full disclaimer.