AVI to MP4 Converter
Convert AVI to MP4 online for free. Change video format for playback, editing, uploads, social sharing, or better compatibility across devices and platforms.
Converting AVI to MP4 re-encodes the video into the MP4 container. Resolution and frame rate are preserved by default, and the audio track is copied without re-encoding when codec compatibility allows. File size depends on the chosen output codec.
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Checking files and selected output formats.
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What to expect when converting AVI to MP4
A 1 GB AVI typically becomes 400 – 700 MB as MP4 with H.264 at the same resolution.
Quality: Re-encoded from the AVI's codec (often older DivX/XviD) to modern H.264. Visual quality is preserved or improved.
Best for: modernizing legacy AVI video files, smaller storage, broad playback compatibility.
Avoid when: the AVI is your only master copy and you don't want any re-encoding loss.
Tip: AVI files from the early 2000s are usually larger than necessary. Converting to MP4 with H.264 keeps the visual quality and roughly halves the file size.
Convert AVI Video in 3 Steps
Re-encode a video for broader playback support, easier editing, smaller files, or platform-specific upload requirements.
Drop your AVI video onto the tool or click to browse. Our converter handles all major codecs including H.264, H.265, VP8, and VP9 inside the AVI container.
Your video is re-encoded into the MP4 container with the optimal codec. Resolution and frame rate are maintained, and the audio track is preserved without re-encoding when possible.
Download your converted MP4 video ready for playback, editing, or uploading to any platform. Files are automatically deleted from our servers within 24 hours.
Why Convert AVI to MP4
MP4 with H.264 encoding is supported by virtually every phone, tablet, computer, smart TV, and game console manufactured in the last decade. No codec packs or special players needed.
H.264 in MP4 delivers excellent video quality at remarkably small file sizes. A two-hour HD movie typically fits in 1-2 GB, balancing quality and storage better than almost any other format.
MP4 supports progressive download and adaptive bitrate streaming out of the box. YouTube, Vimeo, Netflix, and every major streaming platform use MP4 as their primary delivery format.
Instagram, TikTok, Facebook, Twitter, and LinkedIn all recommend MP4 for video uploads. Using MP4 avoids server-side re-encoding that can reduce quality and delay your post.
MP4 containers can embed multiple subtitle tracks, chapter markers, and metadata. Viewers can switch between subtitle languages and jump to chapters without external files.
AVI vs MP4: Side-by-side
Technical comparison of the two formats — useful for deciding which to use, or for confirming what changes during conversion.
| Property | AVI | MP4 |
|---|---|---|
| Full name | Audio Video Interleave | MPEG-4 Part 14 |
| Year introduced | 1992 | 2001 |
| Developer / standard body | Microsoft | MPEG |
| MIME type | video/x-msvideo | video/mp4 |
| File extension | .avi | .mp4 / .m4v |
| Compression | Codec-dependent (DivX, XviD, MJPEG) | H.264 or H.265 codec |
| Color / data depth | Codec-dependent | 8/10-bit |
| Max dimensions / size | Codec-dependent | Codec-dependent (up to 8K) |
| Transparency | No | No |
| Animation | No | No |
| Standard / specification | Microsoft RIFF | ISO/IEC 14496-14 |
| Best for | Legacy video files, archival | Universal video compatibility — plays on every device |
About the AVI Format
AVI (Audio Video Interleave) is a multimedia container format introduced by Microsoft in 1992 as part of its Video for Windows technology. It is one of the oldest video container formats still encountered today. AVI uses a straightforward structure where audio and video data are interleaved — stored in alternating chunks — allowing simultaneous playback of both streams. Its simplicity made it a dominant format throughout the 1990s and early 2000s.
While AVI benefits from broad legacy support and a simple, well-understood structure, it lacks many features expected in modern video formats. It has no native support for streaming over the internet, cannot embed modern subtitle formats or chapter markers, and its compression efficiency depends entirely on the codec used. AVI files also tend to be larger than equivalent MP4 or MKV files. The format is being gradually replaced by MP4 and MKV in virtually all use cases, though it still appears in older video archives and some legacy industrial systems.
AVI to MP4 — Convert Legacy AVI Video to Modern MP4
Key points covered on this page, including compatibility notes, workflow tips, and practical quality trade-offs.
AVI (Audio Video Interleave) is a Microsoft container format from 1992 — older than most of the people watching its content. It still appears in legacy video libraries, downloaded clips, and security camera exports, but it's increasingly poorly supported by modern playback software. MP4 is the universal modern replacement: smaller files, better codec support, plays everywhere.
Why convert AVI to MP4
- Phone and tablet playback — Most mobile devices either refuse AVI or require an extra app. MP4 plays natively.
- Smaller file sizes — AVI files using older DivX or XviD codecs are typically 30-50% larger than the equivalent H.264 MP4 with no visible quality difference.
- Web compatibility — Every browser plays MP4 inline. AVI requires a download.
- Cloud storage previews — Google Drive, Dropbox, and OneDrive preview MP4 but not AVI.
- Streaming and casting — Chromecast, AirPlay, and most smart TVs accept MP4 but stumble on AVI.
- Editing software — Modern editors prefer MP4; AVI requires extra codec packs on Windows and rarely works at all on Mac.
What about quality?
The conversion process re-encodes the video from the original AVI codec (commonly DivX, XviD, or older MJPEG) to H.264 inside the MP4 container. iFormat targets a bitrate high enough to preserve the source's visible quality — the result looks identical on a normal screen, but takes 30-50% less storage.
If the AVI source is already low quality (a compressed download, a security camera export), the MP4 result inherits that quality. Conversion does not improve a poor source — it only changes the format.
File size expectations
- 720p AVI clip, 5 minutes — typically 80-120 MB; MP4 result around 40-60 MB.
- 1080p AVI clip, 30 minutes — typically 1.5-2 GB; MP4 result around 800 MB - 1.2 GB.
- Security camera AVI — already heavily compressed; MP4 result similar size or slightly smaller.
Related video tasks
- Extract the audio track to MP3 — use MP4 to MP3 after converting.
- Need to hit a specific upload size? The Video Compressor targets exact file sizes.
- Converting from QuickTime? Try the MOV to MP4 converter.
- Make a clip into an animated preview with Video to GIF.
How to convert AVI to MP4
- Upload your AVI file (drag-and-drop or click to browse).
- The converter analyzes the source codec and selects the best re-encoding target.
- Click Convert. Larger files take longer — a 30-minute 1080p clip typically takes 2-4 minutes.
- Download the MP4. Original AVI is left untouched on your device.
Uploads are encrypted, processing is isolated per request, and files are automatically deleted within 24 hours (usually within minutes of completion).
Format conversions tested against W3C, ISO, and IETF specifications. Color profiles, alpha channels, and metadata behaviour verified per format pair. Output validated with reference encoders.
- Files processed in your browser when possible
- No email required, no upload tracking
- Server-side uploads deleted within 30 minutes
AVI to MP4 FAQ
Quick answers about compatibility, quality, metadata handling, and the most common reasons to convert AVI files to MP4.
How do I convert AVI to MP4 online?
Why would I convert AVI to MP4?
Will converting AVI to MP4 affect video quality?
How will file size change when converting AVI to MP4?
Why is MP4 a common target for AVI conversion?
Can I batch convert multiple AVI files to MP4?
Is it safe to convert AVI to MP4 online?
Why are old AVI files so much larger than equivalent MP4s?
Will I lose video quality converting AVI to MP4?
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