Compress Files Online — Maximum ZIP Level
Pack any files into a single ZIP archive with your chosen compression level, entirely in the browser.
Processed entirely in your browser — nothing you enter here is ever uploaded.
Result
About this tool
This page opens the ZIP creator with compression level 9 — the maximum — already selected: add your files, press the button and get the smallest ZIP the format can produce.
An honest expectation check: maximum compression works wonders on text, CSV, logs, source code and uncompressed images, but files that are already compressed — jpg, png, mp4, mp3, docx, xlsx — will barely shrink at all, because their data is compressed once already. The tool shows the real size reduction after creation, so you see exactly what level 9 achieved instead of a marketing promise.
Compression happens locally in your browser: nothing is uploaded, and the resulting archive downloads straight from your own device's memory.
Example. Selected files are packed into one ZIP at compression level 0, 6, or 9, keeping folder-relative paths when the picker provides them.
Limit. The archive is not encrypted and is not split across volumes.