Stayput

↑↓ to move, Enter to open, Esc to close. Search runs on this page. Nothing you type is sent.

Convert video to MP4

Turn MOV, MKV and WebM files into MP4s that play everywhere. Converted on this device, never uploaded.

Converts MOV, MKV and WebM videos to MP4. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.

Drop videos to convert to MP4or click to choose files. Batches welcome.
    Details

    H.264 video and AAC sound are copied as they are, so those files convert in seconds with no quality loss. Other formats are re-encoded.

    Working…

    Done

    Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.

    How it works

    1. Drop one or more videos (MOV, MKV, WebM or MP4), or tap to pick them.
    2. Tick Remove the sound if you want a silent video. There is nothing else to set.
    3. Convert. H.264 videos are rewrapped in seconds; others are re-encoded in your browser. One downloads straight away, several download as a zip.

    In your browser, not on a server

    Mediabunny (MPL-2.0), a media toolkit written in TypeScript, reads the MOV, MKV, WebM or MP4 container in your tab. H.264 video and AAC or MP3 sound are copied into the new MP4 packet by packet, which takes seconds and changes nothing in the picture. Other video (VP8, VP9, AV1) is decoded and re-encoded by your browser’s own video encoder through WebCodecs, H.264 where available, and other sound becomes AAC or Opus. The MP4 is written in memory.

    Compared with upload-based tools: Online converters upload the whole video just to rewrap it, which can take longer than the conversion itself, cap free files at 100 MB to 1 GB, and keep a copy on their server. Here the file never leaves your device, and a large MOV from your phone converts in seconds because nothing is re-encoded that does not need to be.

    Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.

    Questions

    Is my video uploaded?

    No. The file is read and written by code in this page, and any re-encoding is done by your browser’s own video encoder. There is no server in the process, so there is no upload and no copy left anywhere. After one visit and a short wait the page works with Wi-Fi off.

    Why was my file converted so fast?

    MOV and MKV files often already contain H.264 video and AAC sound, the same streams an MP4 holds. Those are copied into the MP4 as they are, which only takes as long as reading the file, and the picture is exactly the same as before. The result says "copied, no quality loss" when that happens.

    What about iPhone videos in HEVC?

    Browsers that can decode HEVC (Safari, and Chrome or Edge on a Mac or recent Windows) re-encode it to H.264, which plays everywhere. Elsewhere the HEVC stream is copied into the MP4 unchanged, which plays on iPhones, Macs, Android and Windows 10 or later with the free HEVC extension.

    Which formats can I convert?

    MOV (iPhone, Mac screen recordings, cameras), MKV (OBS recordings, downloads), WebM (browser and screen recordings) and MP4 itself. AVI, WMV and FLV are not supported, because browsers cannot read the video inside them.

    More video and audio tools

    Trim video

    Cut a clip out of a longer video without uploading it. Most cuts take seconds and keep the original quality.

    Mute video

    Take the sound out of a video, in seconds and without re-encoding. The video never leaves this device.

    Resize video

    Change a video’s resolution, from 4K down to 240p or to a width and height you choose. Resized on this device, never uploaded.

    Rotate video

    Turn a sideways or upside-down video the right way up, or mirror it. Done on this device, never uploaded.

    Popular conversions

    Guides