Change a video's format without re-encoding it, wherever that is possible. Most conversions are a change of container around the same picture — those finish in under a second and come back identical to what you uploaded.
Drag & drop a video or click to browse
MP4, MOV, AVI, MKV, WEBM and anything else ffmpeg reads — up to 500 MB
Upload a video, pick the format you need, and get it back. Where the new format does not require re-encoding, none is done: the existing picture and sound are copied into the new container, which takes under a second and leaves the file identical to the one you sent. The work runs on our server with ffmpeg rather than in your browser, so the file can be as large as your connection can carry.
A video file is a box with encoded picture and sound inside it. Turning an MP4 into an MKV usually means changing the box, not what is in it — the same H.264 video and AAC audio are perfectly legal in both. A converter that re-encodes regardless spends minutes of processing to hand back a slightly worse copy of what it was given, and none of it was necessary. We did not assume our copies were really copies: the encoded packets were pulled out of the file that went in and the file that came out and hashed against each other. Eight conversions out of eight matched, on video and on audio. So when this page says nothing was re-encoded, that is a measurement — and the result box tells you which of the two happened, every single time.
Measured here on 2026-09-13, on 30 seconds of 720p30 with four pinned cores:
| Conversion | What happens | Time taken |
|---|---|---|
| MP4 → MKV | Container change — nothing re-encoded | 0.48 s |
| WEBM → MP4 | Container change — nothing re-encoded | 0.23 s |
| AVI → MP4 | Container change — nothing re-encoded | 0.19 s |
| MP4 → WEBM | Full re-encode to VP9 | 33.5 s |
| WEBM → MOV | Full re-encode to H.264 | 7.9 s |
| MP4 → AVI | Full re-encode to MPEG-4 | 5.8 s |
The pattern is the whole story: changing the container is roughly a hundred times cheaper than re-encoding, and it is what most people asking for a conversion actually want. WEBM is the one target that can never avoid the slow path, because the codecs it accepts — VP8, VP9, AV1 — are not what a phone, a camera or a screen recorder produces. A WEBM conversion runs slower than the video plays: thirty seconds of video took 33.5 seconds of work.
Free use is one conversion a day, from files up to 100 MB. A credit pack raises that to 500 MB per file and two hours of video. A conversion that only changes the container is charged a tenth of what a re-encode costs, because that is roughly the difference in the work it takes — you should not pay encoding prices for a second of copying. The 500 MB is the largest body the server accepts. Your upload is deleted as soon as the conversion finishes, and the converted file six hours later.
Not when the streams can be copied, which is most of the time. A copy moves the existing encoded video and audio into the new container untouched, so what comes out is bit for bit what went in — we verified that by hashing both files' streams rather than trusting it, and eight of eight conversions matched on video and on audio. When the format you picked cannot hold what your file contains, a re-encode is unavoidable and a little quality goes with it. The page tells you which of the two happened and names the codec it started from and the one it finished on, so you are never guessing.
Because only some conversions require touching the picture at all. MP4, MKV and MOV will all carry H.264 video with AAC audio, so converting between them is a rewrite of the file's header and index — 0.2 to 0.5 seconds in our measurements, more or less regardless of how long the video is. WEBM accepts only VP8, VP9 or AV1, and MOV will not carry VP9, so those pairs have to be compressed again frame by frame. That is a difference of about a hundred times, which is why this page says which of the two it is doing instead of showing one bar that means two very different waits.
Because it can never copy, and the encoder it needs is a slow one. WEBM accepts VP8, VP9 and AV1; a phone, a camera or a screen recorder gives you H.264, so there is nothing to copy and every frame has to be compressed again with VP9. On four pinned cores that runs at about 0.9 times realtime — thirty seconds of video took 33.5 seconds, and a ten-minute video takes roughly eleven minutes. It is worth the wait when you need a file for the open web. It is a poor choice if what you actually want is something that plays everywhere, which is what MP4 is for.
This is the one place the page deliberately does more work than it has to. ffmpeg will happily put H.264 inside an AVI, and the result reads back fine on this machine — but nobody asks for AVI in 2026 because they like AVI. They ask because something old needs it, and an AVI carrying H.264 is exactly what that old thing cannot open. So an AVI target is re-encoded to MPEG-4 Part 2 with MP3 audio, which is what AVI was built for, unless your file is already in those codecs, in which case it is copied. That cost 5.8 seconds for thirty seconds of video. If you wanted the copy rather than the compatibility, convert to MKV instead.
MP4, unless you have a reason not to. It plays on every phone, browser, television and editor, and converting into it from almost anything is a copy rather than a re-encode. Pick MKV when you need to keep several audio tracks or embedded subtitles, which MP4 handles badly. Pick MOV when Apple software is refusing your file. Pick WEBM only when you are publishing to the open web, and expect to wait. Pick AVI only when something old demands it.
Anything ffmpeg reads — MP4, MOV, AVI, MKV, WEBM, FLV, WMV, MPEG, and the rest of what cameras, phones and screen recorders produce. An audio-only file is refused with a message rather than handed back broken, and so is a file whose only video track turns out to be a cover image. The five targets on offer are the five worth offering: a format nothing can play is not a useful thing to convert into.
A container change is under a second whatever the length, so the upload is the entire wait. A re-encode depends on the target: about 0.9 times realtime for WEBM, about four times realtime for H.264 into MP4 or MOV, and about five times realtime for AVI, on four pinned cores. The page shows an estimate as soon as the server has read your file, and by then it already knows which of the two paths your file is taking — so the estimate is about your video rather than an average of everyone's.
Your upload is deleted as soon as the conversion finishes, and the converted file six hours later. That window exists only so the download link still works if you close the tab and come back to it. Nothing is kept after that, nothing is watched, and nothing is handed to anyone. There is no watermark and no account.