Convert AVI to MP4 Online Free
AVI is a legacy Microsoft video container still found in older files and cameras. MP4 is the most widely supported video container, playable on virtually every device and platform. FileConverter turns your AVI into MP4 online in seconds - free, privacy-first, and with no software to install or account to create.
AVI to MP4 modernises older camera and screen-capture files for editors and browsers that prefer MP4.
What changes when you convert AVI to MP4
This re-encodes your footage from the AVI container into MP4, which can change the underlying codec and file size. At sensible settings quality is well preserved, but converting from a higher-quality AVI source always produces a better MP4 result. Trim long clips first if you only need part of the footage.
About the AVI format
AVI is an older container that can hold high-quality, lightly compressed video, which is why files are often large. It plays on desktop players but is a poor choice for modern web and mobile delivery. In everyday use, AVI is chosen for older recordings and legacy archives and desktop playback of vintage footage. It opens in VLC, Windows Media Player, and most desktop players.
About the MP4 format
MP4 usually pairs H.264 video with AAC audio, giving a great balance of quality, file size, and compatibility. It is the safe default for uploading, sharing, and streaming across phones, browsers, and social platforms. In everyday use, MP4 is chosen for uploading to YouTube, social media, and websites, sharing clips across phones and computers and general-purpose video storage. It opens in all browsers, phones, smart TVs, and media players.
AVI vs MP4
AVI is best known for widely readable on Windows desktop players, while MP4 stands out for plays on essentially every device and player. Choosing between them comes down to where the file needs to go next.
Common use cases
People convert AVI to MP4 for jobs such as uploading to YouTube, social media, and websites, sharing clips across phones and computers and general-purpose video storage. It is especially common when a AVI file arrives from one system but needs to work in another that standardises on MP4.
When to convert AVI to MP4
Reach for AVI to MP4 when your destination expects MP4 — for example uploading to YouTube, social media, and websites, sharing clips across phones and computers and general-purpose video storage. It is the right move when you receive a AVI file but the app, website, or person you are working with cannot use it. Bear in mind that re-encoding from another format is lossy, so keep your original AVI if you might need it again.
How to convert AVI to MP4
- Open the converter with AVI to MP4 pre-selected using the button below.
- Upload your AVI file (drag and drop or browse) within the size limit shown on this page.
- Confirm MP4 is selected as the target format.
- Start the conversion and download your MP4 file the moment it is ready.
Quality tips
Keep one master AVI archived and convert copies. If the MP4 file is for web playback, test it in the target browser or player; if you only need the sound, use our Extract Audio tool instead of a full video conversion.
Platform compatibility
The AVI to MP4 converter works on Windows, macOS, Linux, Android, and iOS - anywhere with a modern browser. No plugins or permissions are required to export MP4.
File size limits
Video/audio up to 2GB
Troubleshooting
- If the file exceeds the limit shown below, compress images, trim video, or split archives before retrying.
- If conversion fails, confirm the extension matches the real format — renaming a file alone does not change its contents.
- Very large videos process faster if you trim them first with our Video Trim tool.
- If quality looks soft, try a less aggressive setting when the converter offers options.
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