26 juin 2026
MP4 vs MOV vs AVI: Which Video Format Should You Use?
MP4 vs MOV vs AVI, explained without the jargon. Learn what each video format is good at, why your file won't play, and which one to keep.
You recorded something on your phone, and now the file is a .mov. Your friend's Windows laptop won't open it. Or you found an old .avi from a camcorder that's somehow 3 GB for ten minutes of footage and won't upload anywhere. Meanwhile every video site on earth seems to want .mp4.
MP4, MOV, and AVI all hold video. They are not interchangeable in practice, and the differences explain almost every "this file won't play" headache you've run into. Here is what each one actually is, and which to keep.
First: the box and the contents are two different things
A video file is really two layers. There's the codec, which is the math that squeezes the moving picture and sound down to a manageable size (H.264, HEVC, and AAC are common codecs). And there's the container, which is the wrapper that bundles the compressed video, the audio, and metadata like timestamps into one file you can double-click.
MP4, MOV, and AVI are containers, not codecs. That distinction matters, because a file can play or fail to play depending on both the box and what's inside it. A .mov that won't open on a PC isn't broken; the player just doesn't know how to read that particular box, or the codec sealed inside it. Keep that two-layer idea in mind and the rest makes sense.
MP4: the one that plays everywhere
MP4 (formally MPEG-4 Part 14) is the closest thing video has to a universal format. It usually holds H.264 video with AAC audio, a combination that every phone, browser, smart TV, and social platform can play without being asked twice.
It compresses well, so files stay reasonably small, and it streams cleanly, which is why YouTube, Instagram, and most web players prefer it. If you only remember one rule from this article: when you need a video to just work somewhere, MP4 is the safe answer.
MOV: Apple's format, great for editing
MOV is Apple's QuickTime container. It's what your iPhone and your Mac's screen recorder produce by default. Technically MOV and MP4 are close cousins. The MP4 standard was actually built on top of the QuickTime format, which is why the two often hold the very same H.264 video inside.
The catch is support. MOV is flawless on Apple devices and in professional editing software, where it can also carry very high quality formats like ProRes for editing. But hand a .mov to a Windows machine, a web uploader, or an older player, and it may stumble even when an equivalent MP4 would have played. MOV is excellent while a video lives inside the Apple world. It gets fragile the moment it leaves.
AVI: the old workhorse, now showing its age
AVI (Audio Video Interleave) is a Microsoft container from the early 1990s. In its day it was everywhere, and very basic players still open it. But it predates modern video by decades, and it shows.
AVI lacks proper support for efficient streaming, modern compression features, and niceties like soft subtitles. Because AVI files often wrap older, less efficient codecs, they tend to be much larger than an MP4 of the same footage. If you have AVI files, they're usually old recordings, and they're usually taking up far more space than they need to.
The .mov that won't play on the client's PC
A freelance videographer films an interview on her iPhone and sends the raw .mov to a client for review. The client replies that the file "does nothing" when double-clicked on their office Windows PC. Nothing is wrong with the footage. The PC simply doesn't have what it needs to open that QuickTime container, and the client isn't about to install codecs to watch a two minute clip.
The camcorder AVI that's too big to share
A dad digitizes a shoebox of old camcorder tapes and ends up with a folder of .avi files. A single twelve minute clip is 2.8 GB. The family group chat rejects it, the email bounces it back, and the cloud folder crawls. The footage is precious, but the format is from another era and the file size makes it almost impossible to pass around.
So which should you use?
For anything you want to share, upload, or watch on more than one kind of device, the answer is MP4. It's the format with the fewest surprises.
| Format | Best at | Watch out for |
|---|---|---|
| MP4 | Sharing, web, social, every device | Almost nothing |
| MOV | Apple devices, video editing | Patchy outside the Apple world |
| AVI | Opening legacy files | Large files, dated, limited support |
Keep MOV while you're editing on a Mac or working in the Apple ecosystem. Keep AVI only long enough to convert it to something current. For everything else, MP4 is what you want to end up with.
Getting any file to MP4
When a video is in the wrong box, you don't need to re-record it. You re-wrap it. Convert any video to MP4 takes a MOV, AVI, WEBM, or MKV clip and repackages it as an MP4 with H.264 video and AAC audio inside, the combination that plays on practically everything. It runs in your browser, so the video never leaves your device, there's no upload, and there's no account to create.
If an old AVI is mostly a size problem rather than a compatibility one, you can also shrink the video down to a size that actually fits in an email or a group chat.
How the videographer gets the client watching
The videographer drops her .mov into the converter and gets an .mp4 back in a few seconds. She sends that instead, and the client's Windows PC plays it on the first double-click, no codecs, no install, no second email. The footage was always fine. It just needed the universal box.
How the dad shrinks the camcorder clip
The dad runs his 2.8 GB AVI through the MP4 converter and the same twelve minutes lands as a far smaller MP4, because H.264 compresses what the old codec couldn't. If it's still bigger than he'd like for the group chat, the compressor trims it down further. The tapes that wouldn't budge now drop into the family thread without a fight.
The short version
MP4 is the format to share and keep. MOV is great while you're editing on Apple gear but travels badly. AVI is a relic worth converting out of. When in doubt, get it to MP4 and your "this won't play" problems mostly disappear.
Ready to get your clip playing everywhere? Try Video to MP4 for free →
Need to slim a file down too? Compress Video → is right here as well.