ZapToolsVideo Compressor
Shrink MP4 videos right in your browser — adjustable quality, fully private.
How it works
FFmpeg runs inside your browser to re-encode your video with H.264. Nothing is uploaded — your footage stays on your device. First run loads the encoder (~25 MB), then it's cached.
Heads up
Browser encoding is slower than desktop software — expect roughly 1–3× the video's length. Keep videos under ~200 MB and close heavy tabs for best results.
Frequently Asked Questions
How long does compression take?
In-browser encoding is slower than desktop: roughly 1–3x the video length depending on your device and settings.
What quality setting should I use?
CRF 28 is a great balance. Use 23 for near-original quality, 32+ for maximum size reduction.
Is my video uploaded anywhere?
No — the video is processed locally with FFmpeg running in your browser.
Why did it fail on a large file?
Browser memory limits apply. Keep videos under ~200 MB and close other tabs for best results.