Secure server conversion
Resize Image to a Specific File Size (KB)
Tell us the size limit and we will hit it. Type 100 KB, or whatever the form demands, and the tool works out the settings itself — no quality slider to guess at, no exporting and checking and exporting again. It is free and needs no account.
A plain number is read as kilobytes. We aim just under your limit, so a form that says “maximum 50 KB” will not reject it on a rounding difference.
Drag & drop your images here
Up to 20 MB per file
→
Could not reach your target without ruining the image. This is the smallest we could manage while keeping it usable — try a larger target.
Step by step
How to hit an exact file size in 4 steps
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Enter your size limit
Pick a preset or type it — "100", "100kb" and "2 MB" all work, and a plain number is read as kilobytes.
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Add your images
Several at once is fine; each is fitted to the same limit independently.
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Check the result
Each file shows the settings that were used, so you can see whether it had to resize as well as compress.
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Download
Your originals are untouched.
Good to know
Why file size cannot be calculated
"Under 100 KB" is an extremely common requirement — job portals, government forms, university and exam registrations, marketplace listings, older content systems — and it is oddly badly served. Most tools hand you a quality slider and leave you to guess, export, check the size, guess again.
The reason nobody just calculates it is that you cannot. The relationship between a quality setting and the resulting file size is not a formula: it depends entirely on the picture. A photograph of a plain wall and a photograph of a forest, identical in dimensions, compress to wildly different sizes at the same setting. Detail, noise and colour variation all change the answer.
So the only reliable method is to encode, measure, and adjust. That is normally tedious, because every attempt means exporting and checking again. Here the tool does it for you: your image is uploaded once, and the server tries eight or ten settings before handing back the best one that fits.
How the search works
It narrows in rather than stepping down, which matters because each attempt is a full re-encode:
- It binary searches the quality scale, so roughly eight attempts cover the entire range — and it keeps the highest quality that fits, not the first one it finds.
- If quality alone cannot get there, it reduces the dimensions and searches again. That is deliberate: past a certain point a smaller sharp image is far better than a full-size smeared one.
- Every attempt re-encodes from your original, never from the previous attempt, so repeated tries never compound compression damage.
- It aims a little under your figure, so a limit of "maximum 100 KB" is not missed over a rounding difference.
Quality
What the tool will and will not do
There is no quality setting to choose, which is the point — but it is worth knowing what the tool will and will not do on your behalf.
It will not destroy your image to hit a number. There is a quality floor, and if reaching your target would mean going below it, the tool reduces the dimensions instead. If even that is not enough, it says so plainly and gives you the smallest usable version rather than pretending it succeeded.
The report tells you what it did. Each file shows the quality it settled on and whether it had to resize. That matters: "quality 88" means your image is essentially intact, while "quality 34, resized to 45%" is a warning that your target is aggressive for that picture.
If a file is already under the limit, it is returned untouched. Re-encoding it would only lose quality for no benefit.
Realistic expectations by target, for a typical phone photograph:
- 500 KB – 1 MB — comfortable. Full size, high quality, no visible change.
- 200 KB — easy for most photos, possibly at slightly reduced dimensions.
- 100 KB — the common form limit. Usually achieved, often with some resizing, and generally still fine for a document or a profile picture.
- 50 KB and below — demanding. Expect noticeable resizing. Fine for a thumbnail or a small ID photo; not for anything printed.
Where these limits come from
- Job portals and application forms, which frequently cap photographs and signatures at 50–200 KB.
- Government and exam registration sites, often with very tight limits and strict dimension rules alongside.
- University applications and scholarship portals.
- Marketplace and classified listings that reject large uploads.
- Email attachment limits, and older content systems with modest upload caps.
Many of these systems give a size limit and a dimension requirement together. If yours specifies pixel dimensions as well, resize to those first and then bring the file here — that way the tool spends its effort on quality rather than undoing a size you needed.
Why resizing beats compressing, past a point
People instinctively reach for compression, but dimensions are the more powerful lever. File size scales with pixel count, so halving the width and height leaves a quarter of the data — a saving no quality slider can match without visible damage.
It is also usually the better-looking outcome. A 400-pixel-wide photo at high quality looks crisp; a 2000-pixel-wide photo compressed hard enough to reach the same size looks smeared at any zoom level. The tool applies that reasoning automatically, trying quality first and only reducing dimensions when it must.
PNG and screenshots
You can drop PNGs in and they will be converted to JPG to reach the target, because JPG compresses photographs far more effectively.
Be careful with screenshots and images containing text, though. JPEG smears exactly the hard edges that make text readable, and a tight size limit makes that much worse. If your image is a screenshot, try PNG compression or converting to WebP instead — both handle text far better at small sizes.
Transparency will be lost, since JPG cannot store it. Transparent areas become white.
Privacy
What happens to your file
This tool runs on our server, so it works the same on every phone and computer. Your file is uploaded, and this is exactly what happens to it:
- Stored outside the public web root under a random name, never under your file's name.
- Processed, with the original upload deleted immediately — whether it succeeded or failed.
- The result sits behind a signed link that only you receive, which stops working after 20 minutes, and the file is deleted the moment you download it.
- Anything never collected is deleted automatically within 30 minutes.
- The image itself is never logged or kept. If a conversion fails, we record the formats involved and the error — not the file.
- Camera metadata, including any GPS coordinates recording where a photo was taken, is removed from the result. Only the rotation needed to show the image the right way up is kept.
Questions & answers
Resize to KB: frequently asked questions
How do I make an image exactly 100 KB?
Type "100 KB" — or just "100" — and add your image. The tool searches for the highest quality that fits under that limit, reducing the dimensions only if quality alone cannot get there. It deliberately aims a little under, so a form specifying "maximum 100 KB" will not reject it over a rounding difference.
Why can the tool not just calculate the right setting?
Because no such calculation exists. The size a quality setting produces depends entirely on the picture — a photo of a plain wall and one of a forest, at identical dimensions, come out wildly different at the same setting. The only reliable method is to encode, measure and adjust, which the tool does for you on our server, from a single upload.
What if my target is too small to reach?
The tool tells you plainly and gives you the smallest usable version it managed. It will not push quality below a sensible floor to hit a number, because a file that meets the limit but is unrecognisable has not solved your problem. Try a larger target, or reduce the dimensions first if your form allows it.
Will it resize my image as well as compress it?
Only if it has to. Quality is tried first, and dimensions are reduced only when quality alone cannot reach your target. Each file reports what was done, so you will see "quality 88" for a comfortable target or "quality 34, resized to 45%" when the target was demanding.
My form also requires specific pixel dimensions. What order should I do things in?
Resize to the required dimensions first, then bring the file here for the size limit. That way the tool spends its effort on quality rather than shrinking an image you needed at a particular size.
Can I use this on a screenshot?
You can, but JPEG handles text badly and a tight size limit makes that much worse — expect smearing around letters. For screenshots, PNG compression or converting to WebP gives a much better result at small sizes.
Keep going
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