Compress Image to 50 KB

Fifty kilobytes is one of the most common upload caps on the web. Exam, visa and job application portals often ask for a passport-style photo under 50 KB (sometimes with a 20 KB minimum), scanned signatures are frequently limited to 20–50 KB, and 50 KB is also a sensible budget for a web thumbnail. This tool finds the highest quality that still fits, so the picture stays as clear as the limit allows. Images are processed in your browser and never leave your device.

How to use this tool

1. Add your photo, signature scan or other image (several at once is fine).
2. Check the maximum (50 KB) and, if the form states one, the minimum.
3. If the form asks for exact pixels (for example 200 × 230), enter the width and height.
4. Download the result and check the size shown under it before uploading.

Formula

For each candidate size, the JPEG/WebP quality q is found by binary search between 50% and 92%: the largest q whose file is ≤ the limit wins. If even 50% is too big, the pixels are scaled by about √(limit ÷ size) and the search repeats.

"Safe" counting uses 1 KB = 1,000 bytes for the maximum (50,000 bytes) and 1 KB = 1,024 bytes for the minimum, so the file passes whichever definition the website uses. When a minimum is set and the JPG is still too small at top quality, invisible comment bytes are added to reach it; the picture itself is unchanged.

Example

A form wants a signature between 20 KB and 50 KB. In safe mode the file must be 20,480–50,000 bytes. A small 400 × 160 signature scan already encodes to only about 9,000 bytes at full quality, so the tool pads it with comment data to exactly 20,480 bytes and reports "Within limit: Yes".

Getting a sharp result under 50 KB

Crop away empty borders first and resize to the pixel size the form asks for — fewer pixels leave more bytes for detail. Photos with plain backgrounds compress far better than busy ones. For a portrait at 50 KB, around 400–600 px on the long side usually looks clean.