AVI – Audio Video Interleave
AVI is an older Microsoft video container from 1992. It is still found in legacy archives, but files are large and browsers do not play them.
More AVI conversionsDrop your AVI files here
or click to choose AVI files · up to 95MB each
How to convert AVI to MP4
- Choose your files. Click Select File or drag your AVI files into the upload box. You can add many at once.
- Pick the settings. MP4 is already selected as the output format. The conversion starts as soon as a file is added.
- Download. Each file appears in the list when it is ready. Download them one by one, or all together with Download all.
Why convert AVI to MP4?
AVI is an old video container, common on cameras, CCTV systems and older downloads. Modern phones, browsers and TVs play MP4 far more reliably, and the MP4 is usually much smaller.
When to keep the AVI
Keep the AVI only if old software or equipment specifically needs it; MP4 is better for everything else.
Tips for the best result
- Video is re-encoded to H.264 and audio to AAC.
- The MP4 is often less than half the size of an old AVI at the same visible quality.
- Odd frame sizes are adjusted by one pixel where H.264 requires even dimensions.
Common problems and fixes
- The AVI will not convert.
- Some CCTV systems use their own codecs inside AVI. Export the clip from the recorder software as a standard video first.
- The sound is out of sync.
- Old AVI files with a damaged index can drift. Try exporting the clip again from the original device or software.
MP4 – MPEG-4 Part 14
MP4 is the most widely supported video container. It usually holds H.264 or H.265 video with AAC audio and plays on nearly every phone, computer, TV and browser.
More MP4 conversionsConverting AVI to MP4
- Re-encoded with widely compatible codecs (H.264/AAC for MP4, MOV, MKV; VP9/Opus for WebM).
Frequently asked questions
Why is AVI so big?
Older codecs used in AVI files compress much less efficiently than H.264.
Will the MP4 play on my phone?
Yes. H.264 MP4 plays on every modern phone.
How do I convert AVI to MP4?
Click Select File or drop your AVI file onto the upload box. The converted MP4 appears in the list below with a download button. You can add many files at once and download them together as a ZIP.
Is it really free?
Yes. There is no sign-up and no watermark. To keep the service available for everyone there is a 95MB limit per file and a cap on how many files one connection can process in a short period.
Are my files stored?
Your upload is used only to make the converted file. Images are processed in memory; other files are written to a private temporary folder that is deleted as soon as the conversion finishes. Nothing is kept after the result has been sent back.
Will quality drop?
For images, a little, by design: the image is re-encoded at the Quality you choose (default 75%). Audio and video are re-encoded with high-quality settings; documents keep their text and layout as far as the target format allows. Converting never restores detail that is already missing from the original.
How this works: your file is uploaded over HTTPS and converted on this server with open-source engines (libvips for images, FFmpeg for audio and video, LibreOffice and Pandoc for documents, Calibre for ebooks, Ghostscript and Inkscape for PDF and vector files). Images are processed in memory; other files use a private temporary folder that is deleted as soon as the conversion finishes.