AVI to MP4 Converter
Convert old AVI video to modern, smaller MP4, free and entirely in your browser. No upload, no watermark.
What is AVI?
AVI (Audio Video Interleave) is a Microsoft container format from the 1990s, still floating around in old camcorder footage, downloaded files, and legacy software exports. It’s an aging format with weak compression and inconsistent codec support across modern devices.
Why convert AVI to MP4?
MP4 with H.264 compresses far more efficiently — an AVI file often shrinks 50–80% when re-encoded to MP4 at similar visual quality — and plays natively on phones, browsers, and streaming platforms that increasingly refuse AVI altogether. Converting is usually the fix when an AVI file "won’t play" on a modern device.
How to convert AVI to MP4
- Drop your AVI file. Drag and drop a AVI file, or click to browse. First use loads the ffmpeg.wasm engine (~31 MB, cached in your browser after).
- Confirm output is MP4. This page pre-selects MP4 as the output format — change it in the format picker if you’d rather export something else.
- Set quality and convert. Pick a quality or bitrate preset, then click Convert. Processing runs locally on your device and typically finishes in well under a minute for short files.
- Download. Click Download to save your MP4 file. Nothing was ever uploaded to a server.
Your file never leaves your browser — conversion runs locally via ffmpeg.wasm, not on a server.
Use Cases
- Modernize old camcorder or webcam footage stored as AVI
- Shrink a bulky AVI file before uploading or emailing it
- Fix an AVI file that a phone or smart TV refuses to play