AVI to MP4 Converter — Convert AVI Files to MP4

AVI files work fine on Windows, but the moment you try to play one on a phone, upload it to YouTube, or send it anywhere, things get complicated. MP4 is what everything expects in 2026 — phones, browsers, editors, streaming platforms. This converter takes your AVI file and outputs a clean MP4 that plays anywhere, without touching the video quality.

No account. No watermark. No file hanging around on a server longer than it needs to.

How to Convert AVI to MP4

Converting an AVI file to MP4 takes about as long as it takes to upload the file.

Step 1 — Upload your AVI file Click the upload area or drag your .avi file directly onto it. You can also drop multiple files at once if you need to convert a batch. The tool accepts any AVI file regardless of which codec is inside it — DivX, Xvid, MJPEG, or uncompressed.

Step 2 — Click Convert The conversion runs on the server, so your device's processor isn't involved. A 500 MB AVI file typically finishes in under 60 seconds depending on your connection speed.

Step 3 — Download your MP4 When it's done, a download button appears. Click it and your MP4 saves to your device. The original AVI and the converted MP4 are both deleted from the server within one hour automatically — sooner if you close the tab.

Why Would You Convert AVI to MP4? The Real Reasons People Do This

AVI is a container format from 1992. It works, but it was built for a world of DVD players and Windows Media Player. Here are the situations where converting to MP4 actually solves something.

Your phone won't play the file

iOS and Android both have limited AVI support. iPhones won't play AVI at all natively. Most Android phones will attempt it, but if the video was encoded with an older codec like DivX or Xvid, the audio drops out or the video stutters. Converting to MP4 with H.264 encoding fixes this because H.264 is what every phone's hardware decoder is built for.

You're uploading to YouTube, Instagram, or TikTok

YouTube accepts AVI uploads, technically. But it re-encodes everything on their end, and AVI files with certain codecs trigger encoding errors or unusually long processing times. Instagram and TikTok don't accept AVI at all — you'll get a format error the moment you try. Uploading MP4 bypasses all of that.

The file is too large to share or send

A 2-hour AVI file encoded with an older codec can easily be 8–15 GB. The same video in MP4 with H.264 at decent quality is usually 2–4 GB. That's not a minor difference when you're trying to send something over email, upload it to Google Drive, or share it with someone on a slower connection. The size reduction comes from better compression — not from reducing the picture quality.

Your video editor won't import the AVI file

Adobe Premiere, DaVinci Resolve, and Final Cut Pro all handle MP4 natively and smoothly. AVI support in these editors is inconsistent — it depends on which codec is inside the AVI container, and if the editor doesn't have that codec installed, it either refuses the file or imports it with no audio. Converting to MP4 first removes that uncertainty.

You're playing the file through a smart TV, media server, or streaming device

Plex, Jellyfin, Kodi, Apple TV, and most smart TVs stream MP4 without transcoding on the fly. AVI often requires transcoding — which uses CPU resources and can cause buffering on lower-powered devices. Storing your videos as MP4 means they play at full quality without the server having to do extra work.

Does Converting AVI to MP4 Reduce Video Quality?

The short answer: no, not in any way you'd notice — and in many cases, not at all.

Here's why. An AVI file is a container, not a codec. Think of the container like a box and the codec as the actual video data inside it. When you convert AVI to MP4, you're mostly just changing the box. If the video inside was encoded with H.264 or H.265, the converter can re-package it into an MP4 container without re-encoding a single frame. That process is called remuxing, and it produces a file that is bit-for-bit identical to the original video content.

The more common situation is that your AVI contains DivX, Xvid, or MJPEG video. In that case, the converter does re-encode — it reads the original frames and re-compresses them using H.264. This is where quality could theoretically drop, but in practice, H.264 at a reasonable quality setting produces output that is perceptually indistinguishable from the source. The kind of quality loss that's actually visible — blocky artifacts, color shifts, blurry motion — only happens when you compress to a very low bitrate. This converter doesn't do that.

When quality loss is genuinely possible: if you convert to MP4, then convert back to AVI, then convert to MP4 again, each re-encode cycle adds a small amount of degradation. Don't do multiple generations. Convert once, keep the MP4.

AVI vs MP4 — Which Format Should You Use?

AVI had a good run. But the honest answer is that MP4 has replaced it for almost every practical use case. Here's what the actual differences are.

Feature	AVI	MP4
File extension	.avi	.mp4
Developed by	Microsoft (1992)	MPEG group (2001)
Container type	RIFF (Resource Interchange File Format)	MPEG-4 Part 14
Common video codecs	DivX, Xvid, MJPEG, uncompressed	H.264, H.265/HEVC, AV1, MPEG-4
Common audio codecs	MP3, PCM, AC3	AAC, MP3, AC3, Opus
Typical file size (1 hr video)	4–15 GB depending on codec	1–4 GB at comparable quality
Streaming support	No — designed for local playback	Yes — used by YouTube, Netflix, HLS
Mobile playback (iOS/Android)	Limited — codec-dependent	Universal — H.264 plays on every device
Subtitle support	External only (.srt files)	Embedded subtitle tracks
Chapter markers	No	Yes
DRM support	No	Yes (optional)

When AVI is still the right choice

Rarely, but it does happen. If you're working in a legacy Windows production environment where the software was built around AVI workflows and hasn't been updated, staying in AVI avoids conversion overhead. Some older broadcast and archival workflows also specify AVI with uncompressed or lossless video, where the lack of compression is intentional.

For personal use in 2026, those situations are uncommon. If you're not sure whether you need AVI, you almost certainly don't.

When MP4 is the right choice

Any time the video needs to leave your computer. Sharing, uploading, streaming, playing on a phone, editing in a modern NLE, distributing to clients — MP4 handles all of it without issues. It's also the format that takes up less storage space, which matters when you're dealing with large libraries of footage.

AVI to MP4 File Size — What to Expect After Converting

The size difference is one of the most common questions, and the answer depends on what codec your AVI file is using.

If your AVI uses an older codec (DivX, Xvid, MJPEG): These codecs were designed in the early 2000s. H.264 — what MP4 uses by default — compresses video far more efficiently at the same visual quality. A 4 GB AVI file can often become 800 MB to 1.5 GB as MP4 without any visible change in picture quality.

If your AVI uses uncompressed or lossless video: Uncompressed AVI files are enormous — a 10-minute 1080p uncompressed AVI can be 50–100 GB. Converting that to H.264 MP4 will produce a file in the range of 500 MB to 2 GB. The quality is still excellent; it's just not bit-perfect lossless anymore.

If your AVI already contains H.264 video: Some AVI files are already H.264 inside the AVI container (unusual but it happens). In that case, the converter remuxes rather than re-encodes, and the output MP4 is virtually the same size as the AVI.

Here's a rough size reference for converted files at standard resolutions:

Original AVI duration	Resolution	Approx. MP4 output size
10 minutes	480p	80–150 MB
10 minutes	720p	150–350 MB
10 minutes	1080p	300–700 MB
1 hour	720p	900 MB – 2 GB
1 hour	1080p	2–4 GB

These figures assume H.264 encoding at a standard quality setting. Actual sizes vary based on the content (static scenes compress more than action sequences) and the original bitrate.

Key Features of This AVI to MP4 Converter

Works with all AVI codec types AVI is a container, not a single format — what's inside varies. This converter handles DivX, Xvid, MJPEG, and uncompressed AVI. If your AVI plays on any computer, it'll convert here.

Batch conversion Upload multiple AVI files at once and download the converted MP4s as a ZIP archive. Useful if you have a folder of old recordings or ripped DVDs that all need converting.

No software to install Everything runs in the browser. Works on Windows, Mac, Linux, iOS, and Android — any device with a browser and an internet connection.

Files are deleted automatically Uploaded AVI files and converted MP4s are removed from the server within one hour. Close the tab and deletion happens immediately. Nothing is retained, logged, or shared.

No account required There's no sign-up gate and no free trial limit. Upload, convert, download. That's it.

Large file support The browser preview is capped to keep things responsive, but the actual conversion handles large files. The download gives you the full output regardless of file size.

Frequently Asked Questions About AVI to MP4 Conversion

Does AVI to MP4 conversion reduce video quality?

In most cases, no. If your AVI contains H.264 video, the converter remuxes it into an MP4 container without re-encoding — zero quality change. If the AVI contains older codecs like DivX or Xvid, the video is re-encoded using H.264, which at standard quality settings is perceptually lossless. Visible quality loss only happens when converting to a very low bitrate, which this tool doesn't do.

How long does it take to convert an AVI file to MP4?

Upload speed is usually the bottleneck, not the conversion itself. A 500 MB AVI file typically converts in 30–90 seconds on a standard broadband connection. Very large files (2–5 GB) may take 3–8 minutes. The conversion runs server-side so your device's processor isn't involved.

What is the maximum AVI file size I can upload?

The upload limit is shown on the tool page. For files larger than the limit, the best option is a desktop tool like HandBrake (free, open source) which handles files of any size locally.

Can I convert AVI to MP4 on an iPhone or Android phone?

Yes. The tool is browser-based and works on Safari (iOS) and Chrome (Android). Tap the upload area to open your file picker, select the AVI file, tap Convert, then download when it's done. The one limitation on mobile is upload speed — large files take longer on a phone connection than on a wired computer.

Why won't my AVI file play on my phone?

iPhones don't support AVI natively at all — iOS has no built-in AVI decoder. Android has limited AVI support that depends on the codec inside the file. DivX and Xvid in particular often fail on stock Android players. Converting to MP4 fixes this because H.264 is built into the hardware decoder of every modern smartphone.

Is my video file safe to upload?

Files are transferred over HTTPS and processed on isolated server instances. They're not accessed by any person, not used for any purpose other than the conversion, and deleted automatically within one hour. If you're working with sensitive footage, use a local desktop tool like HandBrake instead — nothing leaves your machine.

What AVI codecs does this converter support?

The converter handles: DivX (all versions), Xvid, MJPEG, H.264 in AVI container, H.265 in AVI container, and uncompressed AVI. If the codec isn't listed here and your AVI plays normally on a computer, it will almost certainly convert without issues.

Will the audio stay in sync after conversion?

Yes. Audio sync issues in conversion are almost always caused by variable frame rate video, which is common in screen recordings and phone videos saved as AVI. This converter detects variable frame rate and handles it correctly. If you had sync issues with a previous converter, try here — the output should be clean.

How do I convert an AVI file to MP4 without losing quality?

Upload the AVI file using the tool above, click Convert, and download the MP4. The converter uses H.264 at a quality setting that preserves all visible detail. You don't need to adjust any settings — the defaults are calibrated for maximum quality at a reasonable file size.

Can I convert multiple AVI files at once?

Yes — drop multiple AVI files into the upload area at the same time. Each converts independently and you can download all of them as a single ZIP archive.