Video

Video Format Guide — MP4 vs WebM vs MOV vs AVI

Q: What is the difference between MP4 and MOV?

Both use H.264 video, but MOV is Apple's container format (used by iPhones and Final Cut Pro) while MP4 is the universal standard. MOV files play fine on Mac but may need conversion for Windows or web use.

April 21, 2026·5 min read·Convertlo Team

Pick the wrong video format and your file won't play, takes forever to upload, or looks terrible after compression. This guide covers the six formats you'll actually encounter, when to use each, and how to convert between them free in your browser.

The 6 Main Video Formats Explained

MP4 (H.264)

The universal standard. Plays on every device, every platform, every app. Excellent compression with great quality.

✓ Best for: everything — sharing, uploading, streaming

WebM

Google's open web format. Slightly better compression than MP4 at the same quality. Not supported on all devices.

✓ Best for: web video, Chrome/Firefox, HTML5 video

MOV

Apple's container format. Used by iPhones and Final Cut Pro. Identical quality to MP4 but larger file size.

✓ Best for: Apple ecosystem, video editing on Mac

AVI

Microsoft's legacy format from 1992. Large files, wide codec support, no streaming. Mostly replaced by MP4.

✓ Best for: old software compatibility only

MKV

Matroska container — supports multiple audio/subtitle tracks. Popular for movies with subtitles. Not browser-native.

✓ Best for: archiving, media players (VLC, Plex)

WMV / FLV

Legacy formats. WMV is Windows Media Video; FLV was Adobe Flash video. Both largely obsolete — convert to MP4.

✓ Best for: nothing new — convert away from these

Quick Decision Guide

Uploading to YouTube, Instagram, TikTok? → MP4
Embedding on a website? → MP4 (with WebM fallback for best compression)
Editing on Mac? → MOV or MP4, both work fine in Final Cut / Premiere
Movie with subtitles for personal use? → MKV
Have an old AVI/WMV/FLV file? → Convert to MP4
iPhone video? → MOV natively; convert to MP4 for sharing

Convert any video format free

MP4, WebM, MOV, AVI, MKV, FLV, WMV — convert any combination in your browser.

🎬 Convert Video Free →

Why MP4 Wins for Most Use Cases

MP4 with H.264 encoding hits the sweet spot that no other format matches:

Universal playback — works on iPhone, Android, Windows, Mac, Linux, every smart TV, every browser
Platform support — YouTube, Instagram, Twitter, TikTok, Vimeo all accept MP4 natively
Good compression — a 1080p minute of video is typically 100–200 MB
Streaming-ready — supports fast start (moov atom at the front) for web playback

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Frequently Asked Questions

What is the best video format?

MP4 (H.264) is the best all-round format — it plays on every device, has excellent compression, and is universally accepted by social platforms and streaming services.

Can I convert video formats for free?

Yes. Convertlo converts MP4, WebM, MOV, AVI, MKV, FLV, and WMV free in your browser using FFmpeg WebAssembly — no upload, no signup required.

What is the difference between MP4 and MOV?

Both typically use H.264 video encoding, but MOV is Apple's container format (used by iPhones and Final Cut Pro) while MP4 is the universal standard. MOV files work perfectly on Mac but convert to MP4 for sharing cross-platform.

What is the difference between MP4 and MKV?

MKV is a container that can hold multiple audio tracks, subtitle tracks, and chapters — great for movies. MP4 is simpler and more universally compatible. For sharing online, use MP4. For personal movie archiving with subtitles, MKV is fine.

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