AVI to MP4 Converter
Turn old AVI videos into modern MP4 that plays everywhere and takes up far less space — free, no signup, no watermark.
up to 50 files at once
auto-delete in 24h · no signup · no watermark
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How to convert AVI to MP4 online
- Click "Browse Files" or drag your AVI file into the converter above (up to 200 MB free, 500 MB with an account).
- The target format is preset to MP4 — adjust quality options in the picker if you need to.
- Hit "Convert". Your file uploads over an encrypted connection and converts automatically in the cloud — nothing to install.
- Click the green "Download" button to save your MP4 file. The original is deleted immediately and the result auto-deletes after 24 hours.
That is the entire flow — no email address, no software install, no watermark on the output. The page you are reading handles AVI to MP4 from start to finish.
What's the difference between AVI and MP4?
AVI (Audio Video Interleave) and MP4 (MPEG-4 Part 14) solve different problems: AVI is a media container format built for legacy video files, old camera footage, while MP4 is a media container format whose strength is universal video playback and sharing. In practice you will meet AVI when dealing with legacy video files, old camera footage, and reach for MP4 when you need universal video playback and sharing — the table below compares them point by point.
| AVI | MP4 | |
|---|---|---|
| Full name | Audio Video Interleave | MPEG-4 Part 14 |
| Developed by | Microsoft | MPEG (ISO/IEC) |
| Released | 1992 | 2001 |
| Compression | Media container | Media container |
| Typical use | legacy video files, old camera footage | universal video playback and sharing |
| File extension | .avi | .mp4 |
| MIME type | video/x-msvideo | video/mp4 |
Why convert AVI to MP4?
AVI (Audio Video Interleave) is a video container Microsoft introduced in 1992. One of the oldest video formats still in circulation, it lacks modern features like streaming support and efficient codecs, so old AVI files are usually converted to MP4 for use on today's devices. Here is when MP4 is the better choice:
- →MP4 with H.264 plays on every device made in the last 15 years — the safe default.
- →Social platforms, editors, and messaging apps all accept MP4 uploads.
- →It runs in the cloud — 10 free conversions a day with files up to 200 MB (20/day and 500 MB with a free account) — so even a phone or an old laptop converts at full speed.
Before you convert: three quick tips
- ●Video conversion time scales with length — for long footage, trimming to the segment you need before converting saves both time and quota.
- ●Posting to social platforms? MP4 is the universally accepted choice. Short looping clips? GIF. Embedding on a web page you control? WebM is worth considering.
- ●Keep your original AVI — conversion never modifies it, and if you later need a different target format, starting from the original always gives the best quality.
MP4 conversion settings explained
Filevo encodes video with H.264 at CRF 23 using the veryfast preset, with faststart enabled — the engineering balance of compatibility, quality, and speed: the output plays on any device and starts instantly when streamed.
The audio track is encoded as AAC at 128 kbps (higher available in options). Resolution matches the source, auto-adjusted to even dimensions as the encoder requires.
How the conversion works
Filevo's AVI to MP4 conversion is powered by FFmpeg, the open-source media framework behind much of the world's video infrastructure. We run it with compatibility-first settings tuned for everyday playback, and stream progress back to your browser in real time. Because everything runs in the cloud, your device's CPU stays idle — the browser only uploads and downloads.
Why convert AVI to MP4?
AVI is a Microsoft container from 1992 — it predates the web, smartphones and streaming. Modern browsers refuse to play it inline, most phones and smart TVs can’t open it without extra apps, and social platforms reject it on upload. The footage trapped inside is usually fine; the problem is that almost nothing made this century wants to deal with the AVI wrapper. Converting AVI to MP4 moves that footage into the one container every device, browser and app already understands.
There’s a second reason that matters just as much: size. AVI uses old, inefficient compression, so an AVI file is often two to four times larger than the same video as MP4. Converting to H.264 MP4 typically cuts the file size by 30–70% with no visible quality change — that’s smaller storage, faster uploads and clips small enough to actually email or message.
AVI to MP4 is a real re-encode — and that’s the honest answer
Some "instant" converters pretend every conversion is a quick repackage. With AVI that’s rarely true. AVI files almost always contain older codecs — DivX, Xvid or Motion JPEG — that the MP4 container and its players cannot use. So Filevo decodes the original video and re-encodes it to H.264, the codec MP4 was built around. That’s slightly slower than a pure remux, but it’s the only way to produce an MP4 that genuinely plays everywhere instead of a file that merely has the right extension.
Filevo tunes the H.264 encode for compatibility and keeps the quality difference invisible, so the MP4 looks like the AVI — just smaller and universally playable. Resolution, frame rate and aspect ratio are preserved exactly.
Where AVI files come from
Almost every AVI lands on your drive from an older source. If any of these sound familiar, converting to MP4 is exactly what you need:
| AVI usually comes from | Why MP4 fixes it |
|---|---|
| Old camcorders and DV cameras | MP4 imports into any modern editor and phone |
| Downloads from the 2000s | MP4 plays inline in every browser, no codec packs |
| Screen / game recorders (old Fraps, etc.) | MP4 is a fraction of the size to store and share |
| DVDs ripped years ago | MP4 streams to TVs, tablets and Chromecast |
| Legacy software exports | MP4 uploads cleanly to YouTube, Instagram, Drive |
What is AVI?
AVI (Audio Video Interleave) is a video container Microsoft introduced in 1992. One of the oldest video formats still in circulation, it lacks modern features like streaming support and efficient codecs, so old AVI files are usually converted to MP4 for use on today's devices.
| Full name | Audio Video Interleave |
| Developer | Microsoft |
| Released | 1992 |
| MIME | video/x-msvideo |
What is MP4?
MP4 (MPEG-4 Part 14) is a multimedia container standardized in 2001 that bundles video, audio, and subtitles in one file. Usually carrying H.264 video with AAC audio, it is the most compatible video format in existence — every phone, browser, TV, and editor plays MP4.
| Full name | MPEG-4 Part 14 |
| Developer | MPEG (ISO/IEC) |
| Released | 2001 |
| MIME | video/mp4 |
Filevo vs other AVI to MP4 converters
An honest comparison — CloudConvert and Convertio are capable tools; here is where Filevo differs:
| Filevo | CloudConvert | Convertio | |
|---|---|---|---|
| Free tier | 10/day | 10/day | 10 credits/day |
| No signup needed | Yes | Yes | Yes |
| Watermarks | None | None | None |
| Ads on free tier | No | No | Yes |
| Pricing model | 1 file = 1 credit, shown upfront | Per conversion minute | Credit packs |
Privacy & file security
Filevo deletes your uploaded AVI file immediately after conversion and removes the converted MP4 within 24 hours. Everything travels over TLS encryption, processing is fully automated with zero human access, and your files are never used for AI training. See our Privacy Policy for details. Privacy Policy →
AVI to MP4 converter FAQ
How do I convert AVI to MP4 for free?
Drop your AVI file into the converter at the top of this page, confirm MP4 as the target, click Convert, and download the result. It is genuinely free: 10 free conversions a day with files up to 200 MB (20/day and 500 MB with a free account), no watermarks, no software to install, no account required.
Is it safe to convert AVI files online?
Yes. Transfers are TLS-encrypted end to end, and conversion is fully automated — no human ever sees your files. Your uploaded AVI is deleted the moment conversion finishes, and the converted MP4 auto-deletes after 24 hours (you can delete it sooner). We never use your files for AI training or share them with anyone.
Will I lose quality converting AVI to MP4?
Video is re-encoded with H.264 at CRF 23 (veryfast preset) — a quality level that is visually indistinguishable from the source for normal viewing. Keep your original file if you need a frame-perfect master.
How long does AVI to MP4 conversion take?
It depends on length and resolution: short clips typically finish in well under a minute, while longer videos process at roughly real-time speed or faster. Upload time depends on your connection — for large files, uploading is usually the longest step.
Can I convert AVI to MP4 on iPhone or Android?
Yes. Filevo runs entirely in the browser, so it works the same on iPhone, Android, tablets, and computers — no app to install. On mobile, tap Browse Files to pick from your photos or files.
What's the maximum file size?
Anonymous conversions accept files up to 200 MB; a free account raises that to 500 MB. Paid plans go from 1 GB up to 10 GB per file, with higher daily limits and priority queues.
Can I convert multiple files at once?
Yes. Drop up to 50 files at once — they roll through the queue automatically. Pick a target format per file or set one per category, then download results individually or grab everything as a single ZIP.
What codec does the converted MP4 use?
Filevo encodes MP4 with H.264 video and AAC audio with the faststart flag — the most compatible combination, optimized to start playing instantly when streamed.
Does converting AVI to MP4 lose quality?
There is a re-encode step, because AVI’s codecs can’t live in an MP4, but the difference is engineered to be invisible. Filevo keeps the original resolution and frame rate and uses a high-quality H.264 setting, so the MP4 looks the same as the AVI while taking up much less space.
Why won’t my AVI play on my phone or TV?
Most phones, smart TVs and browsers dropped native AVI support years ago — and even when they open the container, they often lack the DivX/Xvid codec inside it. Converting to MP4 (H.264) removes both problems at once: it’s the format those devices are built to play.
Will the MP4 be smaller than my AVI?
Almost always, and often dramatically. AVI’s older compression is inefficient, so re-encoding to H.264 MP4 typically shrinks the file by 30–70% at the same visible quality. A bulky AVI that wouldn’t attach to an email frequently becomes a tidy MP4 that will.
Whether you need universal video playback and sharing or simply a file that works where AVI will not open, the converter above turns AVI into MP4 in seconds — free, private, and with nothing to install. Bookmark this page for the next time a AVI file refuses to cooperate.
Last updated: 2026-07-27