Convert AVI to MP4, Free
Upload your AVI file and get a MP4 in seconds. No account, no watermark.
How to convert AVI to MP4
AVI (Audio Video Interleave) is a container format introduced by Microsoft in 1992. It became the standard for storing video on Windows PCs throughout the 1990s and 2000s. While AVI files can contain high-quality video, they are often much larger than equivalent MP4 files and lack native support on iPhones, iPads, and most streaming services. Converting to MP4 dramatically reduces file size while preserving the original quality.
BoltConverter processes AVI files on its servers using FFmpeg. The video is re-encoded to H.264 and audio to AAC, both of which are the default standard for MP4. Because the conversion is server-side, even large AVI files from camcorders or screen recorders are handled without taxing your own computer.
Upload your AVI file
Click the upload area or drag your AVI video onto the converter. Files up to 100 MB are supported.
Server processes the file
Your AVI is sent securely to BoltConverter's servers and transcoded to H.264 MP4.
Wait for encoding to finish
Large AVI files may take a few minutes. The page shows a live progress status.
Download your MP4
Once complete, click Download. The source AVI is removed from the server right after your download.
Frequently asked questions
Why is AVI so much larger than MP4?
AVI files often contain video compressed with older codecs like DivX or Xvid, without the modern compression of H.264. An equivalent video in MP4 with H.264 is typically 50-70% smaller with no visible quality difference.
Will I lose quality converting AVI to MP4?
The conversion re-encodes the video, which involves a small generational quality loss. For AVI files encoded with DivX or Xvid, the difference is imperceptible at standard viewing sizes.
Can I play the converted MP4 on an iPhone or iPad?
Yes. H.264 MP4 is natively supported by iOS and iPadOS. You can AirDrop it or import it into Photos without any issues.
Is there a size limit for AVI files?
BoltConverter accepts files up to 100 MB. AVI files from longer recordings may exceed this; trimming the clip first or splitting it is the easiest workaround.
Are my files private?
Yes. Files are uploaded over HTTPS, processed, and deleted immediately after conversion. BoltConverter does not retain your video files.