Batch AVI to MP4 Converter
Convert AVI to MP4 online for free. 100% secure, fast, and private local file conversion directly in your browser. No software installation required.
Why convert AVI to MP4?
AVI is a legacy container from the 1990s that still surfaces in old camcorder exports, burned disc rips, and archives of decade-old downloads. Its weak compression means the same footage takes far more disk space than modern formats, and the DivX, XviD, or MJPEG codecs inside many AVI files are unsupported by phones, tablets, and current video editors. Moving AVI to MP4 modernizes the codec as well as the container, so old footage plays everywhere and takes less space.
WasmConvert re-encodes an AVI's dated codec into H.264 with AAC audio inside an MP4 while giving you a quality control that directly trades file size against visual fidelity — useful because AVI files are often several times larger than the equivalent MP4. The conversion runs fully in your browser with no upload step, so even 2 GB archives from old camcorders are processed locally. There is no account, no queue, and no waiting room: you pick the file and the tool does the rest.
Common use cases
- Digitizing old camcorder or MiniDV exports so they play on phones, tablets, and modern TVs
- Shrinking decade-old AVI downloads that eat gigabytes of disk space into compact MP4 files
- Getting DivX or Xvid AVI files into an editor, course platform, or messenger that rejects the format
How to convert AVI to MP4 (Step-by-step)
Select or drop your file
Click "Choose Files" or drag and drop your AVI file directly onto this page.
Set target format
Make sure the output format is set to MP4.
Local conversion
Click convert. Your file is processed entirely in your browser memory - no data is uploaded to our servers.
Save instantly
Once finished, your MP4 file is ready to download.
AVI is a legacy video format introduced by Microsoft. It is often less compressed than modern formats. Converting AVI to MP4 is highly recommended for the web.
MP4 is the most widely supported digital multimedia container format. It is universally compatible with all web browsers, smartphones, and media players.
Pro tips for AVI to MP4 conversion
- AVI files often use MJPEG or raw video from old capture cards, which produce enormous files; re-encoding to H.264 typically cuts size by 80–90% at the same resolution, so do not assume the output must be as large as the source.
- Interleaving damage in old AVI files can make audio drift out of sync with video; if your output desyncs, converting again from the original file (not a re-saved copy) usually fixes it.
- If your AVI is 720×480 SD footage from an old camcorder, keep the original resolution — upscaling to 1080p only adds file size without adding real detail.