Compress Image to 500 KB

Five hundred kilobytes is a common cap on job portals, visa and immigration forms, school applications and marketplace listings — generous enough for a sharp photo or a readable document scan, but well below what a phone camera produces. This tool compresses each image just under the limit, lowering the JPEG quality first so the full resolution is kept whenever that is enough. It runs in your browser, and the images never leave your device.

How to use this tool

1. Add the photos or scans (several at once is fine).
2. Keep the limit at 500 KB or type the one the form states; add a minimum if there is a range.
3. Optionally set a max width or height, or an exact pixel size the form requires.
4. Download the results and check the byte count under each file.

Formula

Highest quality q from 50% to 92% with size(q) ≤ 500,000 bytes, found by binary search in about seven encodes. If even 50% is too large, both sides are scaled by about 0.95 × √(limit ÷ size) and the search repeats.

An image that is already a JPG under the limit is left untouched. "Safe for both" counts the maximum with 1 KB = 1,000 bytes, so a 500 KB limit means at most 500,000 bytes, which also passes sites that mean 512,000 bytes.

Example

A 4032 × 3024 px phone photo of 3.2 MB with a 500 KB limit: if a quality between 50% and 92% brings it under 500,000 bytes, it keeps all 4032 × 3024 pixels. If it is still, say, 650,000 bytes at 50%, the sides shrink by 0.95 × √(500,000 ÷ 650,000) ≈ 0.833 to 3359 × 2520 px and the search runs again.

Documents and scans

For ID cards, certificates and forms, 500 KB is a comfortable budget. Crop to the paper edge and use even lighting: shadows and textured backgrounds use up bytes without adding information.