Video Converter
Any clip into the format the next player or site asks for.
Drop videos to convert
MP4, MOV, WebM, MKV, AVI, 3GP — several at once, all to the same format.
Guide: The format the next place asks for3 min read
The format the next place asks for
Drop one video or several — MP4, MOV, MKV, WebM, AVI, 3GP — choose the format and convert. Each file keeps its name with the new extension, and several come out together in a ZIP. MP4 is the answer for almost everything: phones, TVs, messaging apps and editors. WebM is for websites, MKV for players like VLC and Plex, MOV for Apple's editors and AVI for the old TV or DVD player that will take nothing else.
Copy when it can, re-encode when it must
A video has two layers: the picture and sound tracks, and the container that wraps them. When the tracks already fit the new format — an MKV with H.264 going to MP4, an MP4 going to MOV — only the wrapper is rewritten: identical quality, in seconds. When they do not fit, the tool tries the copy, sees it will not work and re-encodes on its own, without you needing to know which codec is inside.
Re-encoding is real work for the processor, and WebM is the slowest case because it needs VP9; the page warns before you start. To make a file smaller rather than change its format, use compress video; for an iPhone MOV, MOV to MP4 makes every decision for you.
Nothing is uploaded
The conversion is done by ffmpeg running in this tab. The engine is downloaded from this site once and kept, the videos never leave your device, and the only size limit is its memory.
Frequently asked questions
Which format should I choose?
MP4 almost always: it plays on phones, TVs, browsers and every editor. WebM is for putting video on a website. MKV holds any combination of tracks, and is what media players like VLC and Plex are happy with. MOV is for Final Cut and iMovie. AVI is only for the old TV or DVD player that asks for it.
Why was my MKV converted in seconds?
Because the picture and sound inside it were already H.264 and AAC, which an MP4 can hold as they are. Only the container was rewritten, so nothing was decoded and nothing was lost. When the tracks do not fit — VP9 into MP4, anything into AVI — the tool re-encodes instead, which takes real time.
Why is converting to WebM so slow?
WebM needs VP9, and encoding VP9 on one processor thread inside a browser tab is the slowest job this engine does — often a few times the length of the clip. The page warns before you start. MP4 plays on the same websites and is much quicker.
Does converting lower the quality?
Not when the streams are copied. When the video has to be re-encoded, the settings are chosen to look like the original to the eye, and the file may end up larger or smaller than it was. Converting cannot add detail the source did not have.
Are my videos uploaded?
No. ffmpeg converts them inside this tab. The engine (31 MB) is downloaded from this site the first time and kept; the videos never leave your device, and there is no size limit beyond your device's memory.