Compress to Exact Size
Hit an exact file size target such as 50KB, 100KB or 500KB by adjusting quality and dimensions together.
Drop your image here
or click to browse
Processed locally — never uploaded
How to use compress to exact size
- 1Choose your target
Pick the size the form demands. Use the same figure printed on the form, usually 50KB, 100KB or 500KB.
- 2Add your photo
Drop in the image. Leave "only shrink" on if the tool must never scale it up in order to reach the target.
- 3Read the report
The panel shows the final size and precisely which quality and dimensions were used, so you know what was traded away.
About compress to exact size
Compress to exact size is built for upload forms that specify a number rather than a format. Passport portals, government forms, print shops and university submissions all ask for a photo under 100KB or under 500KB, and a generic compressor will not reliably land on that mark.
Ordinary compression works forwards. You choose a quality setting and accept whatever size happens to come out. This tool works backwards instead: it starts from your target and searches for the combination of quality and pixel dimensions that lands just underneath it, giving away as little quality as possible and as little resolution as possible.
Exact sizing almost always needs a second lever. Quality on its own can reach some targets, but a very small budget on a large photograph also needs the dimensions reduced, because a JPEG carries a minimum amount of overhead per pixel. That is why this page controls both, and reports exactly what it changed so you can judge whether the result is good enough for the form.
Frequently asked questions
How does it hit the exact size?
It searches for the highest quality setting whose encoded file still fits your target, and only reduces the pixel dimensions if quality alone is not enough. The result is always at or under your target.
Will it reduce the resolution to get there?
Only when it has to. If a modest quality reduction fits the target, the dimensions are left completely untouched. The panel tells you whenever the image was scaled down.
Why does the result land just under my target rather than exactly on it?
Hitting a figure exactly is not possible, because file size changes in steps as quality moves. The tool aims for the largest file that still fits, which is the useful behaviour when you are up against an upload limit.
What if my image is already smaller than the target?
With "only shrink" enabled the image is simply returned unchanged, since enlarging it would only waste space. Turn the option off if you specifically need a larger file.
Will this work for a passport photo?
It will get the file size right, but you will also need the correct pixel dimensions and usually a plain background. Use the passport photo maker for the layout, then run the result through this tool if the form also sets a size limit.
Are the KB figures the same as my computer shows?
This tool uses 1KB as 1024 bytes, which is the convention web servers and upload forms follow. An operating system that uses 1000 bytes will show a marginally smaller number for the very same file.
Related tools
Private by design. Your files are processed on this device and are never uploaded to the 1xmobcas.com server. Use compress to exact size offline with total confidence.