Convert Video Format
MOV, AVI, MKV, WEBM → MP4. No install, no uploads.
🔒 Files never leave your deviceWhat this tool does
This tool converts videos such as iPhone MOV, AVI, MKV and WEBM into MP4 (H.264 · AAC) that opens almost everywhere, or into WEBM. When a file won't play or won't upload, converting it to MP4 usually fixes it. You can also lower the resolution to 1080p, 720p or 480p to make the file smaller. It runs ffmpeg compiled for the browser (ffmpeg.wasm) on your own device.
How to use
- Choose the output format and resolution (MP4 · Original works for most).
- Add your video — conversion starts right away.
- Keep this tab open and download when it's done.
FAQ
How long does it take?
Re-encoding is slow. On our test desktop, each minute of video took about 1.5 minutes at 720p and about 3 minutes at 1080p. Laptops and phones may take longer. MKV or MOV files that already use H.264 are repackaged in seconds without re-encoding.
Do large videos work?
Everything runs inside your browser, so very large videos can fail when memory runs out. On our test PC (16 GB RAM, Chrome) a 1.1 GB video worked but a 2 GB video failed. Devices with less memory, and phones, may fail with smaller files, so you'll see a warning above 500 MB. For long videos, splitting them first with 'Trim Video' is safer.
Is my video uploaded?
No. Conversion happens in your browser.
Why does the first run take longer?
The first time, your browser downloads the video engine (about 9 MB, roughly 32 MB unpacked). After that it's cached and starts right away.
Tips
- MKV or MOV files that already use H.264, converted to MP4 at 'Keep original', are just repackaged — it takes seconds.
- If iPhone (HEVC) videos won't open on Windows or other devices, convert them to MP4 — they're re-encoded to H.264.
- Keep this tab open while converting. If it's taking too long, click Cancel and lower the resolution, or trim the video into parts first.