How to Export iMovie to MP4 (and What to Do With a .mov You Already Exported)

Export an MP4 from iMovie on a Mac

These are the steps in Apple's iMovie guide:

1. In the browser of projects, select the movie, trailer or clip. iMovie exports one at a time.
2. Choose File → Share → File. In newer versions the same dialog opens from the Share button → Export File.
3. Leave Format on video and audio, and pick a Resolution. A 4K project can be exported at 4K.
4. Set Quality to Medium or Low. Choosing Custom shows a bit-rate slider, and the estimated size under the preview updates as you drag.
5. Click Next, choose where to save it, and click Save. The finished file opens in QuickTime Player.

On iPhone or iPad

Apple's steps: tap the project (tap Done first if it is open), tap the Share button, and choose Save Video, Save to Files or AirDrop. Options sets the resolution: Apple suggests 1080p for most social media and 720p for smaller uploads. If the copy that reaches your computer is a .mov, check its codec as below.

Already have a .mov?

First find out what is inside it. On a Mac, select the file in Finder, choose File → Get Info and look at Codecs under More Info.

• H.264. Apple's own advice is that you can rename the file from .mov to .mp4. If an upload form or a Windows app still refuses it, MOV to MP4 copies the video and audio into a real MP4 container without re-encoding: a 20-second, 11 MB clip took 0.5 seconds when we measured it.
• HEVC (H.265). Also copied, not re-encoded: a five-minute, 70 MB clip took 2.4 seconds. The MP4 is labelled hvc1, the form QuickTime and Photos expect. Windows needs the HEVC extension to play it; switch off "Skip re-encoding when possible" in the advanced options to get H.264 instead.
• Apple ProRes. The converter re-encodes it to H.264, which takes minutes rather than seconds — see the measurements below. If the iMovie project still exists, exporting it again at Medium or Low is the other way.

Converting a ProRes .mov in the browser: what we measured

We made 1080p ProRes 422 files at 24 frames per second with uncompressed stereo audio and converted them on the MOV to MP4 page at its default settings, which re-encode ProRes to H.264 video with AAC audio.

Both MP4s kept every frame (480 of 480 and 1,080 of 1,080) and the full length, at 1080p. Compared with the ProRes source frame by frame, the 20-second clip scored a VMAF of 89.3 on average and 75.2 on its worst frame. Measured on 29 October 2026 in Chrome on a laptop with an Intel Core i7-1165G7 and 16 GB of memory; the test footage was the open-source film Big Buck Bunny, scaled up to 1080p.

The limit that matters: these ProRes files take about 14 MB for every second of 1080p video, and the converter accepts files up to about 667 MB on a computer and 512 MB on a phone, because the whole file has to fit in the browser tab's memory. That is roughly 45 seconds of 1080p ProRes. For anything longer, export again from iMovie at Medium or Low.

Which way to go