How to convert MOV to MP4 on Windows

Step by step

1. Open MOV to MP4. Go to the MOV to MP4 tool in Edge, Chrome or Firefox on Windows 10 or 11. The first visit downloads the FFmpeg engine, about 30 MB, which is then cached.
2. Drop the MOV in. Drag the .mov file onto the drop zone. The tool reads the header and shows the video codec, resolution and duration so you know what you are dealing with.
3. Choose a Method. Pick Remux (seconds, no quality loss) if the codec shows H.264. Pick Re-encode to H.264 (universal, slower) if it shows HEVC or H.265, or if the remuxed file will not play where you need it.
4. Click Convert to MP4. A remux of a 1 GB file takes a few seconds. A re-encode runs at roughly real time to 3x real time for 720p on a recent laptop, so a 2 minute clip takes about 1 to 2 minutes.
5. Download and test. Click Download and open the MP4 in Windows Media Player or Films and TV. If it plays there, it will play on anything.

Why will Windows not play my iPhone MOV file?

Two separate things are going on, and it helps to separate them. MOV is a container, Apple's QuickTime format, and Windows apps are inconsistent about opening it. Inside the container is the actual video, encoded with either H.264 or HEVC (also called H.265). Since 2017 iPhones have defaulted to HEVC under the High Efficiency setting, and Windows cannot decode HEVC without the HEVC Video Extensions, which cost 79p in the Microsoft Store.

So a MOV might fail to play because of the container, the codec or both. Changing the container alone is a remux; changing the codec is a re-encode. Kilnfile's Method option lets you pick, and the codec readout on the drop zone tells you which you need.

Should I remux or re-encode?

Remux when you can. It copies the existing video and audio streams into an MP4 container without touching the pixels, so the output is the same quality and about the same size, and the whole job takes seconds. It only works when the MOV holds H.264 video and AAC audio, which is what an iPhone records under Most Compatible, what a GoPro records, and what most screen recorders and cameras produce.

Re-encode when the MOV holds HEVC, or when the remuxed MP4 still refuses to play on the device you care about. Re-encoding decodes the video and encodes it again as H.264, which every player made in the last fifteen years understands. It takes longer and the file is typically a little larger than the HEVC original, because HEVC is the more efficient codec.

How do I stop the iPhone recording HEVC in the first place?

Open Settings, tap Camera, then Formats, and switch from High Efficiency to Most Compatible. Future videos are recorded as H.264 and future photos as JPG, both of which Windows opens natively. Existing clips are not converted, so run those through the tool. Note that 4K at 60 fps and some slow-motion modes require High Efficiency and will be unavailable with Most Compatible selected.

Does MP4 lose quality compared with MOV?

Not from the container change. MOV and MP4 are closely related formats, and remuxing moves the identical video data from one to the other. Any quality change comes only from re-encoding, and Kilnfile's H.264 re-encode is set at a quality level where the difference is not visible on a phone or laptop screen. If you want a smaller file rather than simply a compatible one, use Compress Video afterwards, where Medium at 720p typically saves 50 to 80 percent.

Is it safe to convert a large video in the browser?

Yes, with one practical caveat. The conversion runs inside your browser tab using FFmpeg compiled to WebAssembly, so the file is never uploaded. Memory is the constraint: files over about 2 GB can exhaust what the browser allows a tab to use. For a long recording, trim it first with Trim Video, or split the job into parts. Keep the tab in the foreground while it works; some browsers throttle background tabs.

Frequently asked questions