Compress Image to Any Size Online

Nearly every upload form on the web enforces a file size ceiling, and the number is rarely round: 100 KB for a visa photo, 2 MB for a job portal, 500 KB for a university admission page, 20 KB for a government ID upload. A phone camera produces files of three to eight megabytes, so almost every photo fails on the first attempt. The usual workaround is a quality slider, which forces you to guess, export, check, and repeat until the number lands under the cap; guessing is slow and usually overshoots. Compressing to a target size inverts that: you state the limit and the tool works backwards to the best image that fits inside it.

This tool asks for the number, not the quality. Once your image is decoded onto a canvas, it binary-searches encoder quality, halving the range after every pass until it finds the highest setting that still lands under your target. That matters because quality is not linear: the gap between quality 70 and 80 can be hundreds of kilobytes on one photograph and almost nothing on another, so any fixed preset is guesswork. Every pass measures the real encoded file instead of estimating from a formula, which is why the result matches the byte budget you set. When no quality level is low enough on a very large original, the tool reduces resolution in gentle 15 percent steps and re-runs the search, stopping the moment the cap is met.

PNG behaves differently, and the tool handles that honestly. PNG is lossless, so the quality argument that browsers accept for JPEG does nothing to it. The tool therefore tries a true-colour PNG first: if that fits your target, you get a mathematically lossless result and nothing else happens. When it does not fit, the tool switches to indexed PNG built from a median-cut palette, stepping down through colour counts until the file fits, and it reserves a transparent palette entry so fully transparent pixels stay transparent. This path matters most for screenshots, logos, and line art, which carry far more detail per byte than photographs do.

Batch work is built in. Drop as many files as you like, set the target once, and each image is measured and compressed independently, so a mixed folder of small screenshots and large camera photos all land under the same cap. Every finished file is listed with its before and after size, the quality or colour count used, the final dimensions, and the percentage saved; anything that cannot reach the target is labelled rather than quietly returned oversized. Downloading everything at once produces a ZIP assembled inside the browser, with no third-party library and no server round trip. Because decoding, encoding, and archiving all happen on your device, nothing is uploaded or retained, and there is no watermark, account, or daily limit.

Use this page when the limit is unusual, when you want to try a few numbers, or when a form states a cap that has no page of its own. If your form asks for a round number such as 100 KB, 200 KB, or 1 MB, the dedicated page for that exact size saves you the typing. Two honest boundaries are worth knowing before you start. A file that is already under your target and already in the format you selected is passed through untouched, so you never receive a larger or re-encoded copy. And this is a compressor, not an editor: it does not crop, it does not resize to exact pixel dimensions, and its output is limited to JPEG, WEBP, and PNG.