Convert video to MP4
Turn MOV, WebM and MKV files into a widely-compatible MP4 — H.264 + AAC for maximum compatibility, or a fast lossless remux when the source codecs already fit. Conversion runs entirely in your browser; nothing is uploaded.
Open Convert video to MP4 →What is Convert video to MP4?
A free, private converter that turns MOV, WebM and MKV videos into MP4 — the format that plays everywhere — entirely in your browser. With Maximum compatibility ticked, the output uses H.264 video and AAC audio, the safest combination for old TVs, office software and every phone. Untick it and the tool does the least work necessary: tracks whose codecs already fit MP4 are copied losslessly (an instant remux), and only incompatible ones are re-encoded. Conversion runs on the browser's WebCodecs engine on your own device — nothing is uploaded and there is no file-size limit.
How to use Convert video to MP4
- Load a video — Drop a MOV, WebM, MKV (or MP4) onto the tool, or click to choose it.
- Choose the compatibility mode — Keep Maximum compatibility ticked for H.264 + AAC, or untick it for the fastest, lossless conversion when you just need the container changed.
- Convert — Click Convert to MP4 and watch the progress — a remux takes seconds, a re-encode runs about as fast as your hardware allows.
- Download — Preview the result and download the .mp4 file.
Frequently asked questions
Is my video uploaded to a server?
No. The conversion runs inside your browser with WebCodecs — it works offline with no size limits.
When is conversion lossless?
With Maximum compatibility unticked, tracks already using MP4-friendly codecs (H.264, HEVC, AV1, AAC, MP3…) are copied byte-for-byte — only the container changes. A WebM with VP8/Vorbis, on the other hand, must be re-encoded.
Why H.264 + AAC?
It's the most universally supported pairing — older smart TVs, PowerPoint, e-mail previews and every phone play it. Newer codecs make smaller files but still meet players that refuse them.
Which input formats work?
MOV, WebM, MKV and MP4 containers, with any codec your browser can decode. Rare professional codecs (e.g. ProRes) aren't decodable in browsers and won't convert.
Tips
- Converting a screen recording (WebM) from the Screen recorder to MP4 makes it attach-and-play in e-mail and chat apps.
- Just need a MOV renamed into MP4-compatible form? Untick Maximum compatibility — Apple MOVs usually carry H.264/AAC already and remux instantly.
- Compress and convert in one go: run the file through Compress video instead and pick MP4 there.