Who needs a specific file size
Many online forms set a hard upload limit: job portals, university admissions, visa and passport applications, exam registrations, bank and identity checks. Typical limits are 20 KB, 50 KB, 100 KB or 200 KB for a photo or signature. A phone photo is usually 2–5 MB, a hundred times too big. Lowering quality by hand until a file fits is slow trial and error. This tool does it in seconds.
How it finds the best quality
- It checks whether the image fits at high quality (92%). If so, you get that.
- If not, it searches between 92% and 30% quality, halving the range each step, and keeps the highest quality that fits under your limit.
- If even 30% is too big, it reduces the pixel dimensions in proportion to how far over the limit the file is and searches again.
The result is the best-looking JPG that stays under your limit. If your file is already a JPG under the limit, it is returned unchanged.
Tips for forms with size rules
- Check pixel requirements too. Many forms also ask for specific dimensions, such as 600 × 600 pixels for a photo. Resize to those dimensions first, then compress to the size limit. The image will look much better than letting the tool shrink it.
- Crop out empty space before compressing, so the limited bytes go into the important part of the photo.
- Signatures scanned on white paper compress very well. 20 KB is usually plenty.
- Plain backgrounds compress far better than busy ones, so a passport-style photo against a wall fits small limits easily.
How to use it
Type a size in KB or pick a preset, then choose or drop your image. The result shows its final size, the quality used, and whether the dimensions changed. Use the preview to check it, then download.
Questions
Why is the result a JPG?
JPG is the format almost every upload form accepts, and it reaches small sizes while keeping photos recognisable. If you start with an iPhone HEIC photo, convert it to JPG first.
Why did my image get smaller in pixels too?
When a photo can't fit under the limit even at 30% quality, the tool reduces its width and height step by step instead of lowering quality further, because very low quality looks blocky. The note next to the result shows the new size.
How close to the limit will the file be?
Usually within a few percent below it. The tool never goes over the limit you set.
Is 1 KB 1,000 or 1,024 bytes?
Forms differ. Windows counts 1 KB as 1,024 bytes, while many websites count 1,000. This tool uses 1,000 bytes, the stricter of the two, so the result passes either way.
Last reviewed 30 October 2026