Video conversion
Convert AVI to MP4
Updated Jul 2026
AVI is an older Windows video format that many phones, browsers, and streaming apps no longer play. MP4 is the format that works almost everywhere. To convert, open the AVI file in a converter and export it as MP4. Doing this on your own computer means the video never has to be uploaded anywhere first.
- Extension
- .avi
- Type
- Video
- Typically
- Legacy Windows video
- Extension
- .mp4
- Type
- Video
- Typically
- The universal video format
- Compression
- Lossy
Convert AVI to MP4 on your own computer. Nothing uploads.
How to convert AVI to MP4
- Open Morphjet and drag in the AVI file, or a whole folder of old AVI clips at once.
- Choose MP4 as the output format.
- Convert. The MP4 is written next to your original, and nothing leaves your machine.
AVI vs MP4: what actually changes
| AVI | MP4 | |
|---|---|---|
| Opens everywhere | No, mainly older Windows software and some media players | Yes, plays on phones, browsers, TVs, and every editor |
| File size | Large, often several times bigger for the same footage | Much smaller, thanks to modern compression |
| Quality | Lossless or near-lossless, depending on how it was originally saved | Very good, with a small one-time loss from compression |
| Streaming and web upload | Often rejected or re-encoded automatically by sites | The standard format sites expect |
| Editing software support | Limited, mostly older or Windows-only tools | Supported by essentially every video editor |
When to convert, and when not to
Convert AVI to MP4 when you want to share an old video, upload it somewhere, play it on a phone or streaming device, or just shrink a folder of bulky AVI files down to a manageable size.
Keep the AVI original if it's your only master copy and you might need the exact source quality later, since MP4 recompresses the video and that step isn't reversible.
Why not just use an online converter?
AVI files often sit around from old camcorders, screen recordings, or downloads, and some people don't think twice about tossing them into a random online converter to get an MP4 out. That means the actual video content gets uploaded to a server you don't control. Converting on your own computer keeps the footage exactly where it started, on your machine.
Questions
Does converting AVI to MP4 lose quality?
A little. AVI is often stored with little or no compression, so exporting to MP4 applies compression for the first time. At a reasonable quality setting the difference is hard to notice, but it isn't the exact same data anymore.
Why won't my AVI file play on my phone or in my browser?
AVI is a container format from the Windows world, and it relies on codecs that phones, browsers, and streaming apps generally don't include anymore. MP4 uses codecs that are supported almost everywhere by default.
Will converting shrink the file a lot?
Usually, yes. Because AVI files are often lightly compressed or uncompressed, the same video saved as MP4 can end up a fraction of the size, which also makes it faster to upload or share.
Can I convert a whole folder of old AVI files at once?
Yes. You can drag in a folder of AVI clips and convert them all to MP4 in one pass, which is common for people clearing out old camcorder or screen recording footage.
Can I convert AVI to MP4 without uploading the video anywhere?
Yes. A desktop app like Morphjet converts the file locally on your own computer, so the footage never has to travel over the internet.
Morphjet converts AVI, MP4, and 1,800+ other formats, all on your machine. Launching this July.