iPhone videos are big because the iPhone records generously: about 60 MB a minute at 1080p and about 400 MB a minute at 4K and 60 frames per second (How much storage does video take? has the full numbers). That's great for quality and awkward for sending, uploading and storage. You don't need an app to shrink them - the iPhone has four built-in ways, and each one gives up something different.
What each method saves, and what it costs
| Method | What you give up | How much smaller |
|---|---|---|
| Trim in Photos | The parts you cut | In proportion to what you cut |
| iMovie at a lower resolution | Sharpness on big screens | 4K to 1080p: several times smaller |
| Shortcuts: Encode Media | Resolution you choose | Roughly half (1080p) to a sixth (540p) |
| Record smaller | Future detail, not existing clips | 4K 60 fps to 1080p 30 fps: about 7 times |
#1. Trim it in Photos
The easiest saving is the footage you don't need: the seconds before the action starts and after it ends. Open the video in Photos, tap Edit, drag the yellow handles at each end of the timeline, tap Done, and choose Save Video as New Clip to keep the original too. The file shrinks in proportion to what you cut, and the part you keep looks exactly the same.
#2. Export a smaller copy from iMovie
iMovie is free from Apple, and it can save a video at a lower resolution. Create a new movie project, add the video and tap Done. Then tap Share, choose Options, pick a smaller resolution such as 720p or 1080p, and save the video. Going from 4K to 1080p makes the file several times smaller; on a phone screen, most people can't see the difference.
#3. Make a "Compress Video" shortcut
Apple's free Shortcuts app can re-encode videos at a chosen size, and once it's set up it lives in the Share menu:
- Open Shortcuts, tap +, and name the shortcut "Compress Video".
- Add the action Encode Media. Tap the arrow to show its options and change Size from Passthrough to a resolution such as 1280×720 - or to Ask Each Time to choose every time.
- Add the action Save to Photo Album.
- In the shortcut's settings, turn on Show in Share Sheet.
- In Photos, open a video, tap Share and choose Compress Video. The smaller copy appears in your library alongside the original.
In one published test, a 178.5 MB clip came out at 76.9 MB at 1080p, 54.2 MB at 720p and 27.6 MB at 540p.
#4. Record smaller in the first place
If storage is the problem, change what the camera records. In Settings → Camera → Record Video, choose 1080p at 30 fps for everyday clips; 4K at 60 fps uses about seven times as much space. In Settings → Camera → Formats, keep High Efficiency selected - it records HEVC, which takes about 40% less space than "Most Compatible". This doesn't shrink videos you've already taken, but it stops the problem growing.
#What about messaging apps?
WhatsApp, Messages and other apps compress videos automatically when you send them, which is quick but takes the choice away from you - and some routes, like texting from an iPhone to an Android phone over MMS, compress very hard. Why videos are blurry when sent from iPhone to Android explains why, and how to send at full quality instead.
#When a computer is the better tool
If you need a video under an exact size - 16 MB for WhatsApp, about 18 MB for an email, 20 MB for Discord - the iPhone's built-in tools can't aim for a number. On a computer, Wave can, in the browser without uploading the video: open Options, pick the size, and it works out the bitrate and resolution from the clip's length. The pages for WhatsApp, email and Discord come with the size already set, and Compress MP4 takes any number.
#Two mistakes to avoid
- Compressing the same video over and over. Each round loses a little more detail. Always start from the original.
- Compressing before uploading to YouTube or Instagram. They re-compress everything, so give them the best version you have (see YouTube upload settings).
#The short version
- Trim in Photos to drop what you don't need - no quality lost.
- Export a 720p or 1080p copy from iMovie (Share → Options), or build a Shortcuts shortcut with Encode Media.
- Record at 1080p 30 fps with High Efficiency to keep future videos small.
- For an exact size limit, use HandBrake on a computer.