How to convert iPhone MOV videos to MP4

You copy a video off your iPhone, send it to a colleague on Windows, and they get sound with a black picture, or an error saying the format is not supported. A course platform or a job portal refuses the upload because it only takes .mp4. The video is fine. The problem is the packaging and the codec inside it.

This guide explains what is actually in an iPhone video, when a built-in setting is enough, how to convert in the browser, and what to expect in size and quality.

What is inside an iPhone video

Two separate things decide whether a video plays:

• The container, shown by the file extension. iPhones save QuickTime .MOV. MP4 is a close relative built on the same structure, but many websites and players only accept the .mp4 extension.
• The codec, which is how the picture is compressed. Since iOS 11, iPhones with the High Efficiency setting record HEVC (H.265). It needs about half the space of the older H.264 for the same picture, but support outside Apple devices is patchy: Windows needs an extra codec extension to play it, older Android phones and smart TVs may not decode it, and many web upload forms reject it.

So there are really two problems, and they need different fixes. Renaming .MOV to .mp4 changes only the label; it sometimes works for H.264 clips, but an HEVC video stays HEVC and fails in exactly the same places.

Check what you have

On a Mac, select the file in Finder and use Get Info: the More Info section lists the codecs, for example HEVC or H.264. On Windows, the file's Properties → Details tab shows resolution and frame rate, though not always the codec. On iPhone, swipe up on a video in Photos to see its resolution, frame rate and size.

As a rule of thumb: videos recorded on an iPhone 7 or newer with default settings are HEVC. Screen recordings and videos received from other apps are usually H.264.

Built-in ways that may be enough

Before converting anything, check whether the device can do it for you:

• Transferring to a Windows PC by cable: on the iPhone go to Settings → Photos and under Transfer to Mac or PC choose Automatic. The iPhone then converts videos to a compatible format during import.
• Playing on a Windows PC: installing the HEVC video extension from the Microsoft Store lets the built-in players open iPhone videos without converting them.
• On a Mac: QuickTime Player can open the video and export it with File → Export As. The result is still a .mov, so it does not help when a site demands the .mp4 extension.

If the requirement is specifically an MP4 file that plays everywhere, a conversion is the reliable route.

Convert in the browser

1. Open MOV to MP4 below and drop one or several files. Each can be up to 2 GB.
2. The first run loads the video engine, about 30 MB, which the browser then caches. The file itself is never uploaded.
3. Download the MP4. Batches can be downloaded together as a ZIP.

What happens inside depends on the codec:

• H.264 video is copied into the MP4 untouched. This takes seconds and loses nothing.
• HEVC and anything else is re-encoded to H.264. That takes longer, roughly real time or slower on a laptop, and much longer on a phone.
• AAC sound, which is what iPhones record, is copied as is.

The output keeps the original resolution and frame rate, so a 4K 60 fps clip stays 4K 60 fps, and a portrait video stays portrait.

For files that are too large or slow for your device, the page also offers server processing with native FFmpeg. It always re-encodes and uses a more efficient encoder setting, which usually gives a smaller file at the same quality. Without an account you get one server run a day for files up to 500 MB.

Do I lose quality

When the source is H.264, no: the picture is copied bit for bit. When the source is HEVC, the video is re-encoded at a constant-quality setting where the difference is hard to see in normal viewing. Every re-encode costs a little, so keep the original MOV if the footage matters to you, and convert copies for sharing.

Why the MP4 can be bigger than the MOV

It surprises people that a 300 MB clip turns into a 450 MB MP4. HEVC is simply more efficient than H.264, so moving to the more compatible codec costs space, and browser encoding uses a fast setting that trades some efficiency for speed.

If the size matters, there are two ways to deal with it:

• Use Compress video instead of the converter. It also accepts MOV, always outputs H.264 MP4, and lets you choose how strongly to compress, so you get compatibility and a smaller file in one step.
• Shorten the clip first with Trim video or remove useless sound with Mute video.

Typical situations

Uploading to a website or form

Upload forms often limit both the format and the size, for example MP4 only and 100 MB at most. Run the clip through Compress video with Medium: it fixes the format and usually the size in one pass. Check the result size before uploading.

Sending to someone on Windows or Android

For a short clip, Compress video is the better choice, since the person on the other end does not need a large file. For a video they will edit, use MOV to MP4 so as little quality as possible is lost.

Playing on a TV from a USB stick

Many TVs play H.264 MP4 but not HEVC, and some are fussy about very high frame rates. Convert with MOV to MP4. If the TV still refuses, record at 30 fps rather than 60 next time.

Editing on a Windows computer

Video editors handle H.264 more smoothly than HEVC on older hardware. Convert before importing to avoid stuttering timelines.

HDR footage

Recent iPhones record HDR video by default. The converter does not tone-map HDR, so the MP4 may look flatter or slightly washed out on some screens. If you mainly share videos rather than watch them on an HDR display, turn off HDR Video in Settings → Camera → Record Video.

Avoid the problem next time

On the iPhone, go to Settings → Camera → Formats and choose Most Compatible. New videos are then recorded in H.264. They are still .MOV files, but because the codec is H.264, converting them to MP4 is a fast lossless copy, and most players handle them without any conversion at all. The cost is storage: H.264 files take roughly twice the space of HEVC, so on a nearly full phone this may not be worth it.

Troubleshooting

• The browser says the file type is not accepted. MOV to MP4 takes QuickTime files only. For MP4 or WebM that will not play, use Compress video, which re-encodes to H.264.
• Conversion stops or the tab crashes on a large file. The browser holds the input and output in memory. A 1.5 GB file on a phone may not fit; use a laptop or the server option.
• Sound but no picture after conversion. Very unusual with the output, which is always H.264. Check that the player is opening the new MP4, not the original.
• The video is sideways. The converter applies the phone's rotation flag, so the MP4 matches what you saw on the iPhone. If the original was recorded sideways, fix it with Rotate video.

Checklist

1. Check the codec: HEVC needs real conversion, H.264 only a quick copy.
2. Use the iPhone's Automatic transfer setting if you only import to a PC.
3. Convert with MOV to MP4 when you need the original quality.
4. Use Compress video when you also need a smaller file.
5. Keep the original MOV for anything you want to archive.
6. Switch to Most Compatible if you regularly share with non-Apple devices.