Free File Compressor

What actually makes a file smaller

• Images are nearly always the problem. A 12 MB document is rarely 12 MB of words. Photographs taken on a phone arrive at far more resolution than a screen or a printed page can show, and re-encoding them is where the saving comes from.
• JPEG quality is a curve, not a line. Dropping a photograph from maximum to high quality often halves the file with no visible difference. Going lower gets small returns and starts to show.
• Some formats are already compressed. A ZIP, an MP4 or a PNG screenshot has had the redundancy squeezed out of it already. You are told when a file has nothing left to give rather than handed back the same size with no explanation.
• Compression is one way. Quality that has been discarded cannot be recovered. Keep the original if the file has to be printed or edited at full quality later.

Worth knowing

• Nothing is uploaded. The file is read and rewritten inside your browser. There is no server copy, no upload limit and no queue — which also means a large file is limited by your own machine, not by a free-tier cap.
• You see the saving before you commit. The before and after sizes are shown, so you can try a different quality if the result is not small enough or not sharp enough.
• Email limits are smaller than you think. Most mail servers reject attachments over 20–25 MB, and encoding inflates a file by about a third on the way out. Aim below 15 MB to be safe.

For PDFs specifically, Compress PDF gives you more control, and PDF to JPG helps when you only need one page as a picture.