VIDEO CONVERTER
MKV, WebM, MOV, AVI → universal MP4 or compact WebM. WhatsApp/iPhone friendly. 100% offline.
MP4, MOV, WebM, MKV, AVI • max 500MB
About Free Video Format Converter (MKV/WebM → MP4)
Turn an MKV that WhatsApp will not open or a WebM your iPhone dislikes into universal MP4 — or make a compact WebM for the web. H.264 + AAC with faststart starts instantly in every player. Fully in your browser.
- ✓Universal MP4: H.264 + AAC, faststart — opens on phones, TVs, WhatsApp, everywhere.
- ✓Compact WebM: VP9 + Opus for lightweight website files.
- ✓3 qualities: high (archive), balanced (daily), small file (sharing).
- ✓Silent video protection: automatically converts silently if there is no audio stream.
- ✓Preview: check your video before converting.
- ✓Zero upload: files never leave your device up to the 500MB limit.
- 1.Select your video or drag it into the area (max 500MB).
- 2.Pick the output format: MP4 for universality, WebM for small size.
- 3.Pick a quality ("Small file" is ideal for sharing).
- 4.Press Convert, preview and download.
Privacy-First Architecture
Unlike 99% of online free video format converter (mkv/webm → mp4) tools, Mr. Robot Help operates entirely on your device. When you upload a file, it never travels to a remote server. Instead, we utilize modern browser technologies like WebAssembly (Wasm) and FFmpeg.wasm to process your data locally.
This approach offers three major benefits:
Your sensitive files stay in your browser's memory. No leaks, no hacks, no logs.
Processing speed is limited only by your CPU, not your internet upload speed.
Since we don't pay for cloud bandwidth, we don't impose artificial file size restrictions.