AVI is a legacy format from the 1990s that's large, often uncompressed, and incompatible with many modern devices. Re-encoding to H.264 MP4 typically reduces file size by 60–80% while producing a file that plays on every phone, tablet, and smart TV.

Free AVI to MP4 Converter Online

Convert old AVI files to modern H.264 MP4 — smaller files, better compatibility.

Create a free account to claim 1000 tokens — enough for about 1000 minutes of 1080p H.264/H.265 or roughly 200 minutes of 1080p AV1 encoding.
Drag & drop a video file here or click to browse
Max file size: 200 MB · Max duration: 300s
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Need More Power?

You’ve tried our free online encoder — but if you need larger files, bulk jobs, or enterprise-grade throughput, Convertrilo has you covered. GPU-powered encoding, predictable pricing, and instant scaling when you need it most.

Frequently Asked Questions

How do I convert AVI to MP4 (H.264) online?

Upload your AVI file using the tool above, make sure the output codec is set to H264 and the container to MP4, then click Convert. No software installation required — encoding runs on our GPU servers.

Is the AVI to MP4 (H.264) converter free?

Yes. No sign-up is required for the free tool. You get up to 720p output and files up to 200 MB. Create a free account to unlock 1080p, larger files, and 1,000 free encoding minutes.

How long does it take to convert AVI to MP4 (H.264)?

Encoding speed depends on file length and selected resolution. Most short clips (under 5 minutes) finish in under 60 seconds on our GPU infrastructure.

What is the difference between AVI and MP4 (H.264)?

H.264 (AVC) is a modern video codec with broad compatibility across virtually all devices and platforms. Converting to MP4 (H.264) is ideal for maximum device compatibility — every TV, phone, browser and player supports H.264.

Will audio be preserved when I convert AVI to MP4 (H.264)?

Yes. By default the tool re-encodes audio to AAC at 192 kbps for MP4/MKV/MOV, or Opus at 128 kbps for WebM. You can also choose to copy the original audio stream unchanged or strip it entirely using the Audio selector.