# Video Converter

> Convert video between MP4, WebM and MKV entirely in your browser.

To convert a video, add your file and choose an output format. MP4 with H.264 plays almost everywhere, while WebM with VP9 produces noticeably smaller files. Conversion runs on your own device using FFmpeg compiled to WebAssembly — nothing is uploaded.

**URL:** https://convertto.tech/t/video-converter
**Category:** Audio & Video Tools (https://convertto.tech/c/media-tools)
**Privacy:** Runs entirely in the browser; no upload
**Cost:** Free, no sign-up
**Last updated:** 2026-08-01

## Key facts

- **Engine:** FFmpeg compiled to WebAssembly
- **First run:** Downloads ~30 MB of FFmpeg core, then cached
- **Upload:** None — the file never leaves your device
- **Privacy:** Runs entirely in your browser — nothing is uploaded
- **Cost:** Free, unlimited, no sign-up

## How to use

1. Select your video file — the file stays on your device and is never uploaded.
2. Choose the convert to.
3. Choose the quality.
4. Choose the resolution.
5. Press Run, then download the result when it is ready.

## FAQ

### Which format should I choose?

MP4 with H.264 for maximum compatibility — every browser, phone and TV plays it. WebM with VP9 for the web when file size matters, typically 25–35% smaller at similar quality.

### Why is the first run slow?

The FFmpeg WebAssembly core is about 30 MB and downloads once per session. After that it stays in the browser cache, and subsequent conversions start immediately.

### Is my video uploaded anywhere?

No. FFmpeg runs inside your browser as WebAssembly, so the file is read from disk into memory and never sent to a server. That is also why there is no file size limit beyond your available RAM.

### Why is it slower than desktop FFmpeg?

WebAssembly runs single-threaded here and cannot use your GPU, so encoding is typically several times slower than a native build. For a short clip that is fine; for a feature-length film, use desktop FFmpeg.

## Related tools

- [MP4 to MOV Converter](https://convertto.tech/t/mp4-to-mov): Convert MP4 video into a QuickTime MOV — usually without re-encoding.
- [Video to GIF Converter](https://convertto.tech/t/video-to-gif): Turn a video clip into an animated GIF with control over frame rate and size.
- [Video Compressor](https://convertto.tech/t/video-compressor): Shrink video file size with adjustable quality — locally, with no upload limit.
- [Audio Converter](https://convertto.tech/t/audio-converter): Convert audio between MP3, WAV, AAC, OGG and FLAC in your browser.
- [Remove Audio from Video](https://convertto.tech/t/mute-video): Strip the audio track from a video without re-encoding the picture.
- [Video Frame Extractor](https://convertto.tech/t/video-frame-extractor): Pull still frames out of a video as images — for thumbnails and contact sheets.
- [Video to MP3 Converter](https://convertto.tech/t/video-to-audio): Extract the audio track from a video and save it as MP3, WAV, AAC or OGG.
- [Video Trimmer](https://convertto.tech/t/video-trimmer): Cut a clip out of a video by start and end time, without uploading it.
- [Screen Recorder](https://convertto.tech/t/screen-recorder): Record your screen, a window or a browser tab with optional audio, straight from this page.