How to convert iPhone MOV videos to MP4

Apple records video in the QuickTime .MOV container, and since iOS 11 usually with the HEVC (H.265) codec. Both choices are fine on Apple devices and painful everywhere else: Android phones, older Windows players, WordPress uploads and most web forms expect MP4 with H.264.

Convert in the browser

1. Open MOV to MP4 and drop the file (up to 2 GB).
2. Wait for FFmpeg — it runs inside your browser as WebAssembly, so the first use downloads a 30 MB engine, then it is cached.
3. Download the MP4. The video is re-encoded to H.264 at CRF 23, which is visually lossless for phone footage.

Do I lose quality?

Re-encoding always costs something, but CRF 23 keeps far more detail than any messaging app will preserve anyway. If the file is for archiving, keep the original MOV as well.

Make it smaller at the same time

MOV to MP4 keeps the resolution and frame rate. If you also need a smaller file — for email or WhatsApp — use Compress video instead: it accepts MOV directly and lets you choose how aggressive the compression is.

Avoid the problem next time

On iPhone go to Settings → Camera → Formats → Most Compatible. New recordings will be H.264 in an MP4-compatible container, and you can skip this page in future.