Click to choose an AVI or drop it here
AVI in, MP4 out — converted in your browser, never uploaded. Other video types work too.Video and audio are processed in your browser by FFmpeg (ffmpeg.wasm), free software under the GPL-2.0-or-later and MIT licenses — licenses & source.
About converting AVI to MP4
To convert AVI to MP4, drop your .avi file on the box above and press Convert to MP4. You get an MP4 with H.264 video and AAC sound — the format that plays on iPhones, Macs, Android, smart TVs, web pages and in every video editor.
Most AVI files are old: from a camcorder, a digital camera, a DVD rip or an old hard drive. The video inside is usually DivX or Xvid, which modern phones and browsers no longer play. This tool turns it into a modern MP4, and if your AVI already holds H.264, it simply repacks it in seconds.
Everything runs in your browser. Your video is never uploaded.
Features
- MP4 that plays everywhere — H.264 video and AAC sound
- Fast repack when the AVI already holds H.264 — seconds, no quality loss
- DivX and Xvid — old videos are re-encoded so phones, TVs and browsers can play them
- Quality choice — High, Good or Smaller file
- Optional resize — 1080p, 720p or 480p, for a smaller file
- Honest result — the page tells you if it repacked or re-encoded
- Private — no upload, no sign-up, no watermark
What is an AVI file?
AVI means Audio Video Interleave. Microsoft made it in 1992, for Windows. For about 15 years it was the normal video file on PCs, and many cameras saved AVI too.
An AVI is a container: a box with a picture track and a sound track inside. The box is simple and old. It has no good support for modern codecs, subtitles or streaming. Inside, you usually find:
- DivX or Xvid video (MPEG-4 Part 2) — the most common, from the 2000s
- MJPEG — from old digital cameras, a series of JPG pictures
- H.264 — in some newer AVI files
- MP3 or uncompressed PCM sound
Why MP4 plays everywhere
MP4 with H.264 video is the standard video file today. Every phone, computer, TV, browser and editor plays it.
| Where you play it | AVI (DivX/Xvid) | MP4 (H.264) |
|---|---|---|
| iPhone and iPad | No | Yes |
| Mac (QuickTime, Photos) | No | Yes |
| Android phone | Some apps | Yes |
| Windows 10 and 11 | Yes | Yes |
| Smart TV from a USB stick | Some, often older TVs | Yes |
| Web browser on a web page | No | Yes |
| iMovie and many video editors | Often not | Yes |
| WhatsApp, Instagram, Facebook | No | Yes |
| VLC (any computer) | Yes | Yes |
Why not just repack every AVI?
Repacking moves the video into a new box without touching it. It takes seconds and loses nothing — so the tool does it whenever it gives a good file.
But DivX and Xvid video is allowed in an MP4 and still does not play in Chrome, Safari, on most phones or on many TVs. A quick repack would give you an MP4 that looks right and then shows a black screen. So for DivX, Xvid and MJPEG, this tool re-encodes the picture to H.264. That is the step that makes the file play everywhere.
How fast is it?
- AVI with H.264 video — repacked in a few seconds.
- AVI with DivX, Xvid or MJPEG — re-encoded. This runs in your browser on one processor core, so it takes time: often about as long as the video, sometimes longer, and slower on a phone. Old AVI files are often small (480p or less), which helps a lot.
Tips for a faster result: choose Smaller file or a lower Resolution, and cut the clip first with Trim Video if you only need part of it.
How to use it
- Click the box and choose your AVI, or drag it onto the box
- Leave Quality on *Good* — choose *High* if you will edit the video later
- Leave Resolution on *Keep the original*, or pick a lower one for a smaller file
- Press Convert to MP4 and wait — you can switch tabs, but keep this one open
- Play the result, then press Download MP4
Frequently asked questions
How do I convert AVI to MP4 for free?
Drop the AVI on the box on this page and press Convert to MP4. It is free, with no sign-up and no watermark, and the video stays on your device.
Will I lose quality?
If the AVI holds H.264, it is repacked with no change at all. A DivX or Xvid AVI must be re-encoded; on *Good* or *High* quality the difference is very hard to see, and the MP4 is often smaller than the AVI.
Why does it take so long?
Old AVI video has to be re-encoded to H.264, and that work runs on your own computer, in the browser. A short or small video is quick; a long HD video takes a while. The page shows the progress.
Can I play an AVI on an iPhone or Mac?
Not in the built-in apps. Convert it to MP4 here, and it plays in Photos, QuickTime, iMovie and on the iPhone.
Is there a file size limit?
There is no upload limit. The limit is your browser's memory: files up to about 1–2 GB usually work on a computer. Phones handle less.
Is my video uploaded?
No. The converter (ffmpeg) runs inside your browser, on your device. The video never leaves it.
Related tools
- MKV to MP4 — the same job for MKV files
- Video Converter — convert to MP4, WebM or MKV from many formats
- MOV to MP4 — for iPhone and QuickTime videos
- Trim Video — cut out the part you need
- Compress Video to Size — make the MP4 fit a size limit
- MP4 to MP3 — keep only the sound
Credits
Conversion is powered by ffmpeg.wasm (FFmpeg and x264, licensed under GPL-2.0).
