Convert AVI videos to MP4 free online — 10x smaller, plays everywhere. No upload, no watermark.
Max file size: 500 MB · Files are processed locally in your browser, nothing is uploaded.
100% free · Converted locally in your browser · Your videos never leave your device
First run loads the video engine (~30MB, one time).
AVI is a container from 1992 — ancient in internet years. Most AVI files use old, inefficient codecs (or no compression at all), which is why a 10-minute AVI can easily exceed 1GB while the same video as MP4 fits in 100MB. Worse, modern phones, browsers, and smart TVs often refuse to play AVI entirely. Converting to MP4 typically shrinks the file 5–10x and makes it playable everywhere.
This is the perfect tool for digitized family videos, old camera footage, and downloads from the 2000s gathering dust on a hard drive. One conversion brings them into the modern era: small enough to share, playable on any device.
This tool runs FFmpeg, the industry-standard video engine, compiled to WebAssembly and executed entirely inside your browser tab. Your video never travels over the network — check your browser's network tab if you like. Old family footage stays private, and huge AVIs don't need uploading (which could take hours on slow connections).
AVI (Audio Video Interleave) was designed by Microsoft in 1992 for CD-ROMs. It usually wraps outdated codecs like DivX, Xvid, or raw uncompressed video — enormous files by today's standards. MP4 with H.264 is 20+ years of compression research newer: same visual quality at a tenth of the size, with hardware decoding support in every phone and TV. There is no reason to keep videos in AVI anymore except archival purism — and even then, a high-quality MP4 is the more practical archive.
One honest note: conversion can't restore detail lost in the original AVI's old compression, but it preserves everything that's there while making the file dramatically smaller and universally playable.
Yes — unlimited conversions, no account, no watermark. Everything runs on your device.
No. Conversion happens locally via FFmpeg in WebAssembly inside your browser. The video never leaves your device — good news for gigabyte-sized AVIs.
Typically 5–10x smaller. A 1GB AVI often becomes a 100–200MB MP4 with no visible quality loss, because AVI codecs are decades less efficient.
No — conversion preserves the existing quality but can't add detail that isn't there. What you gain is size and compatibility, which is the whole point with AVI.
Yes — files are processed locally and never uploaded. For irreplaceable footage, keep a backup of the original AVI before converting, as good practice.
Your browser downloads the FFmpeg engine (~30MB) on first use, then caches it. Later conversions start immediately. Large AVIs also take longer to encode — that's normal.
Yes in any modern mobile browser. Note that phones have less memory — very large AVI files (1GB+) are better converted on a desktop.