How-to
Convert an iPhone video to MP4 that plays everywhere on Windows
iPhones save video as HEVC inside a .mov file by default. Modern browsers and recent Windows versions can usually play that combination already, but some older programs, video editors and upload forms still expect an MP4 file with H.264 video instead. The video converter reads the .mov file, decodes the HEVC video stream and re-encodes it to H.264 inside an MP4 container, entirely on your device, so no file is uploaded to get there.
Step by step
- Open the video converter and drop the .mov file from your iPhone. It is read locally in your browser tab, and video/quicktime files are accepted regardless of which codec is inside.
- Keep the default output settings: MP4 as the container and H.264 as the video codec. That combination is what nearly every Windows app, video editor and upload form expects.
- Click Convert. The HEVC video track is decoded and re-encoded to H.264, the audio track is re-encoded to AAC, and the result is offered as an MP4 download. The original .mov file on your device stays untouched.
Why iPhone videos come as HEVC in a .mov file
Since iOS 11, the iPhone camera has saved video using the HEVC (High Efficiency Video Coding, also called H.265) codec inside a QuickTime .mov container by default, because HEVC compresses roughly twice as efficiently as the older H.264 at a comparable quality, which matters on a phone with fixed storage. Playback support for HEVC is now built into most current operating systems and browsers, but a range of older Windows programs, some video editing suites, and some website upload forms are still built around H.264 in MP4, and either reject the .mov file outright or fail to preview it correctly.
What actually happens during conversion
Converting the file means decoding every frame of the HEVC video stream and re-encoding it, frame by frame, with libx264, ffmpeg's H.264 encoder, then muxing the result with a re-encoded AAC audio track into a new MP4 container. This runs through ffmpeg compiled to WebAssembly inside the browser tab, so nothing about the file is sent anywhere. A full decode-then-encode pass like this is CPU-intensive, unlike a simple copy operation, so a short clip converts in seconds while a recording several minutes long can take a few minutes on a typical laptop.
What this conversion changes, and what it does not offer
The output is H.264 video in an MP4 container, which gives up some of HEVC's extra compression efficiency: expect the converted file to be somewhat larger than the original .mov at matching visual quality, which is the trade-off for wider compatibility. Only H.264 and VP8 are offered as output codecs. HEVC, H.265, VP9 and AV1 are not available as conversion targets, because their encoders do not complete reliably in this browser-based WebAssembly engine. If a smaller file matters more than maximum compatibility, compress the converted MP4 afterward instead of looking for a newer output codec.
What to expect: processing time, file size and limits
Because the whole file is decoded and re-encoded on your own device rather than on a server, a several-minutes-long recording takes noticeably longer to convert than a short clip, and the browser tab needs to stay open while it works. Files up to 500 MB are accepted; very large or very long recordings use more memory while the conversion runs, so closing other tabs helps on devices with less RAM. If you specifically need a smaller file rather than a more compatible one, run the result through the video compressor afterward.
The tools used in this guide
Frequently asked questions
Is my video uploaded anywhere during this conversion?
No. The HEVC decode and H.264 re-encode both run inside your browser tab, using ffmpeg compiled to WebAssembly. The .mov file is read into local memory, processed there, and the resulting MP4 is saved straight to your device. No frame of the video is sent over the network.
Do I really need to convert, or can Windows already play HEVC .mov files?
It depends on the app. Windows 11, VLC and current browsers can already play an HEVC .mov file directly in many cases, sometimes after installing a small HEVC extension. Convert it when a specific program refuses the file, shows a black or corrupted preview, or when you need to import it into an editor or upload form that only accepts MP4 with H.264 video.
Will the converted MP4 keep HEVC's smaller file size?
No. The output uses H.264, which is older and less efficient than HEVC, so the converted MP4 is typically somewhat larger than the original .mov at the same visual quality. That size increase is the cost of the much wider playback and editing compatibility that H.264 in MP4 provides.