Reduce Image Size in KB

Type the limit your form or website gives you. You get the sharpest JPG that stays under it, checked to the byte, without uploading anything.

Maximum file size

Every file comes out at 100,000 bytes or less, so it passes forms that count 1 KB as 1,000 or as 1,024 bytes.

Minimum size (optional, some forms set one)

or drop them here, or paste with Ctrl+V. JPG, PNG, WebP, up to 20 at once. They never leave your device.

How it works

Type your limit
Enter the maximum your form or website gives, in KB or MB, or tap one of the presets. Add a minimum if the form sets one.
Add your images
Choose files, drop them on the box or paste a screenshot. Up to 20 at once, nothing is uploaded.
Check and download
Each result shows its exact size in KB and in bytes. Change the limit and every image is redone; download one file or a ZIP.

Why a size limit, not a quality slider

Most compressors ask you for a quality percentage and leave you to guess. You lower it, download, check the file size, and start over when it is still 3 KB too big. When a form says "maximum 100 KB", the only number that matters is the file size.

This tool works the other way round. You give it the size, and it tries quality settings until it finds the highest one that fits. Only if even a low quality is too heavy does it make the picture smaller, because a smaller sharp photo reads better than a large blocky one.

How many pixels fit in each size

Size in KB depends on the number of pixels and on how much detail the picture has. As a rule of thumb, from our own measurements:

Largest long side of a photo that fits each size at JPEG quality 80
Limit	Long side at good quality
20 KB	330 – 470 px
50 KB	560 – 770 px
100 KB	860 – 1,140 px
200 KB	1,170 – 1,600 px

For reference: measured on five real photos (landscapes, a workshop interior, a screenshot) at JPEG quality 80. A plain background fits more pixels, a busy one fewer. The tool itself keeps the full size whenever a quality of at least 50 fits, and only then shrinks.

Getting the best result

Crop first. Every pixel of background you remove is quality kept for the face or the text.
Start from the original, not from a screenshot of it or a photo sent through a chat app, which is already compressed.
For a document, a flat even light gives a far smaller file than a shadowed photo of a page.
If a form also gives exact dimensions in pixels, resize to those first, then come back here for the size.

Questions

How do I reduce an image to a specific size in KB?

Type the size in the box (or tap a preset), then add your image. The tool searches for the best JPEG quality under that limit, shrinks the dimensions only if it has to, and shows the final size in KB and in bytes before you download.

Will the result always be under the limit?

Yes, whenever it can be done without making the image unreadable, and the result says so in green with the exact byte count. If a very busy image cannot get under a tiny limit, the tool tells you instead of handing you a file that would be rejected.

Why is the output a JPG?

JPEG is the format every upload form accepts, and the only common one that can hit an exact size by adjusting quality. PNG files are lossless, so they can only get smaller by losing pixels. Transparent areas become white.

My image is already small enough. What happens?

If it is a JPG already under the limit, you get the very same file back, untouched, metadata included. There is no point re-compressing it and losing quality. Every file the tool does compress comes out without its camera metadata (date, phone model, location).

Is 1 KB 1,000 or 1,024 bytes?

Both are in use, and forms rarely say which. That's why the tool aims under the stricter one: a 50 KB file here is at most 50,000 bytes, which is also under 51,200 bytes. The exact byte count is shown next to every result.

Are my photos uploaded anywhere?

No. The page compresses them inside your browser with the canvas built into it. Your files never reach a server, so ID cards, signatures and certificates stay on your device. You can even switch off your connection once the page has loaded.