Convert video
MP4, WebM, GIF, or extract audio as MP3 - all locally in your browser.
About this tool
Convert videos between formats - MP4, WebM, MOV, MKV, AVI and more - with control over the video and audio codec, the container and the target bitrate. Great for hitting upload requirements (Instagram wants MP4/H.264, archival often wants MKV), shrinking files, or making something playable on an old phone.
Conversion runs in your browser via FFmpeg-WebAssembly. Your source video is never uploaded, which matters for raw camera footage, client work, or anything you'd rather not hand to a random web service.
Features
- Output containers: MP4, WebM, MOV, MKV, AVI
- Video codecs: H.264, H.265 / HEVC, VP9, AV1
- Audio codecs: AAC, Opus, MP3
- Quality (CRF) or bitrate-based encoding
- Resolution and frame-rate overrides
- 100% browser-side - files never leave your device
- Free, no signup, no watermark
How to use it
- Drop in your video file.
- Pick the target container, video codec and audio codec.
- (Optional) set CRF / bitrate, resolution and frame rate.
- Click Convert. Conversion runs locally - large files take a few minutes.
- Download the converted file.
Everything happens inside your browser using JavaScript and WebAssembly. Your files are never uploaded to a server, never stored, and never seen by us.
Frequently asked questions
FFmpeg-WebAssembly runs single-threaded inside one browser tab, so it's slower than native FFmpeg on the same machine. A 10-minute 1080p clip can take 5-15 minutes depending on your CPU. The trade-off is privacy - your file never leaves your device.
H.264 in MP4 is the safest universal choice. H.265/HEVC and AV1 give better quality at the same bitrate but have less consistent browser support.
Constant Rate Factor - a quality setting where lower numbers mean higher quality and bigger files. 18 is visually lossless, 23 is the default, 28 is 'okay for web'.
Yes - the audio codec is whatever you pick. If you want to keep the original audio bytes, the trim tool's stream-copy mode does that for trimming; full conversion always re-encodes.