MOV to MP4
Turn a MOV into an MP4 that plays anywhere.
iPhone and QuickTime videos are MOV files. Drop one and get an MP4 with the video and sound formats every player knows (H.264 and AAC), converted on your device and never uploaded.
Needs a browser that can make video itself. Tested in Chrome and in WebKit, the engine behind Safari; Firefox is not tested.
Drop a video here.
Drop a video here.Choose a video.
MP4MOVWEBMMKVNothing leaves this device.
Several files of one kind convert together.
How it works
Drop it, check MP4, save it.
1
Drop the MOV
From the Files app, a desktop folder or an AirDrop. Several at once is fine.
2
Leave Plays everywhere selected
If the video already uses H.264 and AAC it is only copied into the MP4, which takes seconds and keeps every pixel. Otherwise it is converted.
3
Save
The MP4 starts playing as soon as it loads, not after it is fully downloaded, because its index is written at the front.
Measured examples
Copied in a blink, or converted.
Two generated 20-second 1080p clips, one with H.264 video and one with HEVC, both written as MOV files.
| Test file | Size | Change | Time | Result |
|---|---|---|---|---|
| 20 s clip, 1080p, H.264Chrome | 30 MB → 30 MB | Same size | 190 ms | Video stream identical · Copied, no quality lost |
| 20 s clip, 1080p, H.264WebKit | 30 MB → 30 MB | Same size | 1.1 s | Video stream identical · Copied, no quality lost |
| 20 s clip, 1080p, HEVCChrome | 25 MB → 32 MB | 25 percent larger | 3.3 s | Video converted |
| 20 s clip, 1080p, HEVCWebKit | 25 MB → 20 MB | 20 percent smaller | 7.9 s | Video converted |
Measured on November 7, 2026 in Google Chrome 157, WebKit (Playwright build, not Safari) 26, on Apple M1 Pro. Times run from pressing Convert to the result being ready, with the page already loaded. Likeness is PSNR against the original: higher is closer, and above 40 dB the difference is hard to see. WebKit here is Playwright's build, which is not Safari. Every test file was generated for these measurements, none is anyone else's work, and each is described on the About page.
The H.264 clip was copied into an MP4 in 193 milliseconds, and its video packets are byte for byte the ones in the MOV. The HEVC clip had to be converted to H.264: 3.3 seconds, and the file grew from 25 MB to 32 MB. WebKit, which uses its own H.264 encoder, made 20 MB from the same HEVC clip, in 7.9 seconds: the size after a conversion depends on the browser.
Facts
Two boxes, close relatives.
MOV and MP4
Both are containers built on the same box structure, which is why H.264 and AAC move between them without any conversion.
H.264 with AAC
Copied into the MP4. No pixel is touched, and the length matched to the millisecond in our test.
HEVC and 10-bit video
Converted to 8-bit H.264, which every player handles. The file is usually bigger afterwards.
Rotation and frame rate
Kept. A portrait clip stays portrait, and variable frame rate stays as recorded.
Good to know
What is inside a MOV.
MOV is a container, not a codec, which is why some MOV files convert instantly and others take a while.
Container versus codec
MOV and MP4 are boxes that hold video and sound streams, and they are close relatives. When the streams inside are H.264 and AAC, converting is just moving them into a new box: no re-encoding, no loss, a few seconds even for a big file.
An iPhone set to High Efficiency records HEVC (H.265) instead. That is not welcome on every player, so Flex Convert re-encodes it to H.264. Settings, Camera, Formats, Most Compatible makes new recordings H.264 from the start.
What a re-encode does to size
HEVC squeezes more than H.264, so converting HEVC to H.264 at the same quality makes the file bigger: our HEVC test clip went from 25 MB to 32 MB. Flex Convert sizes the bitrate from the source's own bits per pixel so it does not inflate files needlessly.
If the file is too big afterwards, use the compress page: it targets a size instead.
What it keeps
Portrait videos stay portrait, frame rate stays as recorded (variable frame rate included), and 10-bit HEVC is converted to the 8-bit H.264 every player handles. Odd picture sizes are rounded up to even ones, so 1279 by 719 becomes 1280 by 720.
The browser must be able to play the video to convert it. ProRes MOV files, from professional cameras, are refused with a message.
When to keep the MOV
Apple devices, Final Cut, Premiere and DaVinci Resolve open MOV directly, so converting a file you will only edit buys nothing. Convert when the video is going to a Windows PC, a TV, a website or a person you cannot ask what player they use.
If something goes wrong
When it does not work.
Most problems are about what is inside the MOV, not the MOV.
Couldn't open this file
Why: The MOV holds ProRes or another professional format that a browser cannot decode, or the file is damaged.
What to do: Export an H.264 or HEVC version from the editor or camera app, then convert that.
The MP4 is bigger than the MOV
Why: The MOV used HEVC, which packs more into each byte. In Chrome our HEVC test clip grew from 25 MB to 32 MB; WebKit's encoder made it smaller.
What to do: Use the compress page to set a size, or set the iPhone to Most Compatible so new recordings are H.264.