Compress PNG to 100 KB
Compress a PNG file to under 100 KB, keeping PNG 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. The output here is PNG, so anything with transparency or sharp text keeps its edges — but see the note below about what that costs in size.
- There is nothing to set. This page is already fixed at under 100.0 KB, PNG.
- Check the result. PNG is lossless, so if the target could not be reached at a usable size the panel explains why instead of handing you a thumbnail.
PNG is lossless, which means it ignores quality settings entirely. The only way to shrink a PNG is to reduce its pixel dimensions or its colour count — so this tool scales the image down in steps until it fits. If your image is a photograph rather than a graphic, converting to JPEG will produce a far smaller file at the same visual quality.
Compress PNG to 100 KB — the specification
| Target file size | Under 100 KB |
|---|---|
| Output format | PNG |
| Method | Dimension reduction — PNG is lossless and ignores quality settings |
| Transparency | Preserved |
Compress PNG 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 image is a photograph saved as PNG. PNG cannot compress photographic detail well — a JPEG of the same image is often five times smaller.
- You needed transparency but the target size is very small. Transparency forces PNG, which limits how far the file can shrink at a given size.
- The dimensions had to drop a long way to reach 100 KB. Check the result is still usable.
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 then binary-searches the quality parameter: encode, measure, halve the remaining range, repeat. The run below took 7 encodes to land at 99.1 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.
All of it runs locally through the browser’s canvas API. PNG encoding is the slowest thing this site does, so a very large image can take a few seconds on a phone — that is your own device working, not a queue.
A measured run of this exact preset
Not an estimate: this page’s own code, run against a 12.2 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 |
|---|---|---|---|
| 12.2 MP photograph 3024 × 4032 px · 2.94 MB | 99.1 KB 196 × 261 px | 97% smaller | Under the 100 KB limit |
| A4 scan at 200 dpi 1654 × 2339 px · 996.0 KB | 99.4 KB 205 × 289 px | 90% smaller | Under the 100 KB limit |
Step by step
PNG has no quality dial, because it stores every pixel exactly. The only lever is pixel count, so the tool searched the scale instead — 7 encodes, narrowing from 147.7 KB to 99.1 KB.
Final file: 99.1 KB, using 99.1% of the allowance, with 877 B to spare.
Who needs Compress PNG to 100 KB
Situations where the output format is fixed — a form that accepts only PNG, or a workflow where the format must not change.
Compress PNG to 100 KB — frequently asked questions
Why keep PNG rather than convert?
PNG preserves transparency and stays lossless, which matters for logos, screenshots and graphics with sharp edges. If your image is a photograph and you do not need transparency, JPEG is a better choice.
Why does quality not affect PNG size?
PNG compression is lossless — it reconstructs the image exactly, so there is no quality dial to turn. Size is determined by dimensions and colour complexity, which is why this tool scales the image instead.
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 PNG. 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 measured run needed no meaningful scaling — the target was reached on quality alone, so the image keeps its full dimensions. If the form allows this much, you give up very little.
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 | 50 KB | 137 × 183 px | — |
| 100 KB (this page) | 99 KB | 196 × 261 px | — |
| 200 KB | 199 KB | 280 × 373 px | — |
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.