Convert Video
Turns a MOV, MKV, WebM or MPEG-TS file into an MP4, or an MP4 into a WebM. When the new container will hold the codecs the file already uses, the tracks go straight across without being encoded again, which takes a moment and loses nothing.
Runs entirely in your browser. Your files are never uploaded.
How to use Convert Video
- 1Choose a video, or drag it onto the box.
- 2Pick MP4 or WebM.
- 3Leave the pictures as they are for a straight repackage, or pick a quality to re-encode them.
- 4Convert, then download.
Most conversions are not conversions
A MOV from a Mac and an MP4 from a phone usually hold the same thing: H.264 video and AAC audio. The difference is the box around them and where the index sits. Changing that means reading the tracks out of one container and writing them into another, with the compressed frames passed through untouched.
So the file that comes out is the same video in a wrapper more things will open, and it takes about as long as copying the file: a 9.3 MB clip was repackaged in 63 milliseconds in testing. The page says when this is what is happening, and it is the default whenever it is possible.
Re-encoding is the other case, and it is slower and loses a little quality, which is why it is not done unless it has to be. An MKV holding HEVC cannot be repackaged into a WebM, because WebM takes VP8, VP9 and AV1 and nothing else.
Which one to pick
MP4 with H.264 is the safe answer. Every phone, television, editor and browser plays it, it is what social platforms expect on upload, and it is the only format you can hand to someone without asking what they will open it with.
WebM with VP9 is smaller at the same quality, usually by around a quarter, and it plays in every current browser. It is the right choice for video on a web page you control. Older software and most televisions will not touch it, and neither will a few editing suites.
Nothing here writes HEVC. Browsers can often decode it and almost none will encode it, so offering it would mean a button that fails on most machines.
What this will not open
AVI, FLV, WMV and RealMedia do not open here. These are old containers whose own codecs browsers never shipped, and no amount of reading the file helps when there is nothing to decode it with.
HEVC and ProRes files often open and sometimes do not, because decoding them depends on the machine rather than the browser. The page checks before offering to convert and says so when the answer is no, rather than running for a minute and then failing.
Limits
- 500 MB per file.
- Output is MP4 or WebM. There is no AVI, MOV or MKV writer here.
- Repackaging needs the codecs to suit the container. MP4 takes H.264, VP9 and AV1; WebM takes VP8, VP9 and AV1.
- Subtitle tracks are not carried across.
- A re-encode to VP9 often comes out well under the estimate. On test footage it landed 43 percent below, because VP9 spends less than it is offered.
Frequently asked questions
- Does converting MOV to MP4 lose quality?
- Not when it is a repackage, which it usually is. The compressed frames are moved into the new container exactly as they were, so the picture is identical. The page tells you when that is what it is doing.
- Why is my conversion instant?
- Because nothing was encoded. The tracks already suited the container you asked for, so they were copied across. Only re-encoding takes real time, and the page says which of the two happened.
- Can it convert an AVI?
- No. Browsers have no AVI support at all, so the file cannot even be read here. VLC and HandBrake both handle them, and once it is an MP4 everything on this site will take it.
- MP4 or WebM for my website?
- WebM if you are serving it yourself and your visitors are on current browsers, since it is around a quarter smaller. MP4 if the video also has to work in an email, on a television, or in software you do not control.