Convert AVI to MP4
Convert AVI to MP4 online free. Fast, private and in your browser — no upload, no sign-up and no watermark. Batch AVI→MP4 conversion that works on any device.
To convert AVI to MP4, drop your AVI file into the converter above, then download the MP4 result. It's free, needs no sign-up, and there's no watermark. Conversion runs in your browser with on-device FFmpeg, so your files never leave your device.
Why convert AVI to MP4?
Convert AVI to MP4 to modernise old video files. AVI is large and dated; MP4 (H.264) is smaller, streams with fast-start and plays on every modern phone, browser and platform.
- Modernising old AVI footage for today's devices.
- Shrinking large AVI files for upload and storage.
- Making legacy video streamable and shareable.
AVI vs MP4
AVI · Audio Video Interleave
AVI is an older Microsoft container. It's widely readable on desktops but produces large files and lacks modern features like streaming-friendly fast-start, so it's usually converted to MP4.
MP4 · MPEG-4 Part 14 (H.264)
MP4 with H.264 video is the most universally compatible video format — it plays everywhere and uploads cleanly to YouTube, Instagram, TikTok and messaging apps.
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Open Video ConverterAVI to MP4 — frequently asked questions
How do I convert AVI to MP4?
Drop your AVI file (or several) into the converter, confirm MP4 is selected as the output, click convert, then download the MP4 file. The whole thing takes a few seconds.
Is this AVI to MP4 converter free?
Yes — it's completely free with no watermark and no sign-up required.
Is it safe to convert AVI to MP4 here?
Yes. Conversion runs on-device with FFmpeg compiled to WebAssembly, so your AVI file is never uploaded to a server.
Can I convert multiple AVI files at once?
Add your AVI file and convert it, then repeat for the next one — each runs locally in your browser.
Does it work on mobile?
Yes — the converter runs in any modern browser on phones, tablets and desktops.