The short answer
MOV and MP4 are both containers: boxes that hold the video, the audio and some information about them. What decides the quality is what's inside, the codec, and in practice MOV and MP4 files usually hold exactly the same codecs: H.264 or HEVC for the picture, and AAC for the sound.
MOV is Apple's QuickTime format. MP4 is an international standard that was based on it. They're close relatives, which is why converting one to the other can be done without re-encoding anything.
Side by side
| MOV | MP4 | |
|---|---|---|
| Made by | Apple (QuickTime) | International standard (MPEG-4) |
| Recorded by | iPhones, many cameras | Most Android phones, screen recorders |
| Usual video inside | H.264 or HEVC | H.264 or HEVC |
| Quality | Same as MP4 with the same codec | Same as MOV with the same codec |
| Compatibility | Good on Apple devices, patchy elsewhere | Plays almost everywhere |
When MOV causes problems
- Upload forms that only accept MP4, such as some job sites, government portals and school systems.
- Older Windows programs and some smart TVs.
- Video editors on Windows that don't recognise the file.
If you hit any of these, converting to MP4 is the fix.
Convert MOV to MP4 without losing quality
- Open the Altols MOV to MP4 converter.
- Choose your MOV file. It stays on your device.
- Click Convert to MP4 and download the result.
Altols copies the existing video and audio into an MP4 container rather than re-encoding them, so the conversion takes seconds and the quality is identical. If you also want a smaller file, use the MOV compressor instead, which saves an MP4 at the size you choose.
What about iPhone videos that won't play?
If a MOV from an iPhone won't play on Windows even after converting, the video inside is probably HEVC, which some Windows computers need an extension for. Setting your iPhone to Settings → Camera → Formats → Most Compatible records H.264 instead, which plays everywhere. See how to change your iPhone's camera format.