Convert Video Format – Free Online Tool
Convert videos between different formats. Support for MP4, WebM, AVI, MOV, and more.
Example Output
Convert between MP4 / MKV / MOV / WebM / AVI containers and re-encode video/audio codecs as needed. Stream-copy when codec/container are already compatible.
movie.mp4 (1080p H.264, primary audio, AAC) — universally playable
What is Convert Video Format?
Convert videos between the major containers — MP4, MKV, MOV, WebM, AVI — and re-encode video and audio codecs if needed. When the source codec is already compatible with the target container, the tool stream-copies (instant, lossless). Otherwise it transcodes with sensible defaults.
Why use this tool?
- Open-and-go: bookmark the page once and never look for an alternative
- Instant results — no waiting on a server or upload progress bar
- Touch-friendly UI, fine on phones for on-the-go edits
- First-load downloads the WASM core once (~30 MB), then subsequent edits are fast
- No video upload — clips of any length stay on your local machine
How to use
- Upload your video file
- Select output format
- Click "Convert Video"
- Download the converted file
Examples
MKV → MP4 for compatibility
An MKV file plays on Linux but not on an iPad. Convert to MP4 (H.264 + AAC) and it plays everywhere.
MOV → WebM for the web
A QuickTime MOV becomes a WebM optimised for HTML5 `<video>` autoplay in modern browsers.
AVI → MP4 for archiving
A legacy AVI with DivX video converts to a modern MP4 with H.264 — smaller, more compatible, easier to play.
Common use cases
- Cross-device compatibility (Mac ↔ Windows ↔ iOS ↔ Android)
- Preparing video for HTML5 web playback
- Modernising legacy AVI / WMV files
- Replacing proprietary container with open one (or vice versa)
- Standardising mixed-format folders to one format
Troubleshooting
- Output won't play on iOS
- iOS requires H.264 video + AAC audio in MP4. Pick those explicitly instead of "copy codec" — the source codec may be unsupported.
- Multi-channel audio collapsed to stereo
- Toggle "preserve all audio channels" — default is to downmix surround to stereo for compatibility.
- Subtitles missing after conversion
- Subtitles are a separate stream. Toggle "include subtitle streams" to copy them. MP4 supports mov_text; for SRT, keep MKV.
Frequently Asked Questions
Input: MP4, WebM, AVI, MOV, MKV, FLV, 3GP, M4V and most other common containers. Output: MP4 (H.264/AAC), WebM (VP8/Vorbis), AVI (MPEG-4/MP3), and MOV (H.264/AAC).
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