JPG Compressor
Compress JPG and JPEG files to a size you set, keeping JPEG as the output format.
Leave blank for best quality with no size limit.
Finding the best quality that fits…
- Original
- —
- Result
- —
- Reduction
- —
- Dimensions
- —
How to use this tool
- Select your file, drag it onto the box above, or paste it from your clipboard.
- Processing starts automatically — there is nothing to configure.
- Check the result panel, which shows the original size, the final size and the output dimensions.
- Click Download to save it.
JPEG is already a compressed format, so the tool re-encodes at a lower quality rather than applying a second compression layer on top. That is why it always works from your original rather than from a previous result.
The specification
| Input | JPG / JPEG |
|---|---|
| Output | JPEG |
| Target size | Whatever you enter, in KB |
| Quality search | Seven steps, keeping the largest file that fits |
| Maximum input | 25 MB |
Why uploads get rejected
Meeting the size is only part of it. These are the failures that actually come up:
- You compressed an already-compressed JPEG repeatedly. Each pass permanently discards detail and artefacts accumulate. Always start from the original.
- The photo has very large pixel dimensions relative to the target, so quality has to drop a long way.
- The image is really a PNG renamed to .jpg — the browser will still read it, but the output will be a genuine JPEG.
How it works
Most compressors pick a fixed quality level and hope for the best, which is why they either overshoot the limit or land far below it and throw away detail you did not need to lose.
This tool runs a binary search instead. It encodes your image at a mid-range quality, measures the resulting file, then narrows the range — higher if there is room, lower if it is over — repeating seven times. It keeps the largest result that still fits. If the lowest quality is still too big, it reduces the pixel dimensions and searches again.
All of it runs on your own device using the browser's canvas API. Nothing is transmitted.
Who uses this
Photographers, sellers and anyone emailing or uploading photos who needs them smaller without changing format.
Frequently asked questions
Does compressing a JPG again lose quality?
Yes. JPEG is lossy, and every re-encode discards more information. One pass from the original is far better than three passes from previous outputs.
What quality does it use?
Whatever the highest quality is that still fits your target — found by binary search rather than fixed in advance.
Will the quality drop?
Some quality is always lost when a file gets smaller — that is what compression means. The tool searches for the highest quality that still fits under your limit, so it gives up as little as possible.
Are my files uploaded to a server?
No. Everything runs inside your browser on your own device. Your file is never transmitted and never stored by us. You can confirm this by opening your browser’s Network tab while you use the tool — you will see no upload request.
Is there a limit on how many files I can process?
No. There is no daily cap, no account, and no watermark. Because the work happens on your device rather than our servers, there is nothing for us to ration.
Is this tool really free?
Yes — no account, no trial, no watermark, and no cap on usage. It runs on your own device rather than our servers, so there is no cost for us to pass on.
Does it work on mobile?
Yes. The interface adapts to phone and tablet screens, and everything runs in the browser, so there is no app to install.
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Your files stay on your device. This tool runs entirely in your browser. No file is uploaded, transmitted, or stored. You can verify this by opening your browser's Network tab while using the tool.
Disclaimer. Specifications published by exam boards, governments and platforms change without notice. We verify and date every specification on this site, but you should always confirm against the official source before submitting an application. See our full disclaimer.