Convert AVI to MP4 online for free. Change video format for playback, editing, uploads, social sharing, or better compatibility across devices and platforms.
Max file size 10MB. Sign up for more.
| File Name | Size | Convert To |
|---|
Checking files and selected output formats.
| File Name | File Size | Download |
|---|
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.
AVI → MP4 handles legacy Windows video files (early 2000s camcorder recordings, screen captures from older utilities, archive digitisations). MP4 gets you universal playback and platform-upload compatibility. Some old AVI files use codecs (DivX, XviD) that need re-encoding — the conversion isn't always as fast as MOV → MP4 which is often just a container swap.
MP4 (with H.264 video and AAC audio) is the universal video format — plays on every phone, TV, browser, and video-editing app. Convert to MP4 when uploading to YouTube, Instagram, TikTok, or any platform that doesn't specify otherwise. MP4 is the default output for smartphone recording and the expected format for shared / embedded video.
Same footage, different container. Get a file that plays where you need it to, with sensible defaults for codec, bitrate, and framerate.
Free-tier uploads are capped at 10 MB — fine for short clips and screen recordings, tight for anything long-form. Pro handles files up to 1 GB and batch jobs of up to 20 videos. Because video work is compute-heavy, sign-in is required on the free plan for anything past a minute of source video.
The defaults for MP4 are set to the most-compatible codec for that container (H.264 for MP4, VP9 for WebM, and so on). If you want a smaller file at the same quality, pick a modern codec like H.265 — but check where the video's going first, because older devices can't play H.265.
Video conversion takes proportionally longer than audio or image work — roughly a few seconds per second of source video on a typical 1080p clip. The output downloads immediately once ready, and both the source and result are deleted from our servers within 30 minutes.
A file called AVI tells you almost nothing about what's inside — the container is a box that could hold several different codecs. The codec is what actually determines quality, size, and compatibility. Converting AVI to MP4 usually means picking a new codec too; the defaults above are what most people expect to work everywhere.
Six scenarios where the format swap is the actual job — not incidental to something else.
Recent iPhones save videos as MOV wrapped around H.265, which older Windows machines and many web apps can't decode. Converting to a widely-supported MP4 makes the clip playable everywhere.
HTML5 <video> reliably plays MP4 across every mainstream browser. Some formats (MOV, MKV, unusual containers) trigger downloads instead of playing inline. Converting to MP4 first avoids the "why isn't this playing" support thread.
Final Cut loves MOV/ProRes. Premiere handles most things but chokes on variable-framerate phone MP4s. DaVinci Resolve wants specific codec support. Converting to what your editor actually understands prevents hours of debugging "why is playback laggy".
Email caps attachments at 25 MB. Slack's free plan tops out at 1 GB. Form portals often insist on under 100 MB. A modern codec-swap (H.264 → H.265) typically cuts size 40-60% at the same quality — usually enough to fit the limit without touching resolution.
Old AVI files, ancient FLV downloads, MPEG-2 rips from a decade ago — legacy formats work but eat disk space. Converting to a modern MP4 halves storage without losing quality, and future-proofs the collection against the day players stop shipping with legacy decoders.
YouTube, Instagram, TikTok, and LinkedIn all publish their own "recommended encoding" specs. Converting to a spec-matching MP4 before upload skips the platform's own re-encode and produces cleaner playback quality.
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 |
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.
Quick answers about compatibility, quality, metadata handling, and the most common reasons to convert AVI files to MP4.
Read format, playback, upload, and editing guides related to AVI to MP4 Converter.
The complete guide to video file formats — MP4, MKV, AVI, MOV, WebM, FLV, and WMV explained. Understand the difference between containers and codecs, and learn which format works best for streaming, editing, and sharing.
iFormat's online video converter supports MP4, MOV, WebM, AVI, MKV, and more. Convert any video format free, no software required.
PowerPoint to PDF freezes your deck into read-only pages. Here's what actually survives (animations don't) and how to compensate.
That two-hour lecture recording as MP4 is unlistenable on the train. Convert it to MP3 to strip the video and keep just the audio you actually need.
iPhone videos in MOV won't play on Android or in WhatsApp status. Here's how to convert to MP4 — plus what to expect on file size and quality.
iPhone HEIC photos that Windows can't open — here's the fastest way to convert them to JPG without installing anything, plus the workarounds that actually work.
