There is no single number, and anyone who gives you a precise one is guessing. The size of an hour of iPhone video depends on resolution, frame rate, format — and, surprisingly, on what you are filming. But you can get close enough to plan, and you can measure your own.
Why the size varies
iPhone video is compressed. The encoder spends more data on detail and movement and less on still, dark scenes. A lecture hall with one person talking compresses far better than a lit stage with moving lights and a crowd, so two one-hour recordings at the same settings can differ noticeably.
The settings matter more:
- Resolution. 4K has four times the pixels of 1080p. It does not take four times the space, but it takes a lot more.
- Frame rate. 60 fps takes more than 30 fps.
- Format. In Settings → Camera → Formats, High Efficiency makes files considerably smaller than Most Compatible at similar quality.
The quick estimate
Open Settings → Camera → Record Video. For each option, iOS shows roughly how much space a minute of video takes in the Camera app. Multiply by 60 for an hour, then by the length of your event.
The accurate way: measure your own
- Record one minute of something similar to what you will film, with the app and settings you will use.
- Check the file size — swipe up on the video in Photos, or look at the file in the Files app.
- Multiply by the number of minutes you plan to record, and add a margin. A quarter more is sensible.
A budget to plan with
NoLight has to decide before a recording starts whether there is room for it, so it budgets deliberately high: about 7 GB per hour at 1080p and about 22 GB per hour at 4K. Real recordings usually come in below that. If your phone has that much free, you are safe; if it is close, measure.
For a 90-minute concert, that is up to about 11 GB at 1080p, or about 33 GB at 4K.
Free up space before a long session
- Settings → General → iPhone Storage shows what is using the space, and can offload apps you do not use.
- Recently Deleted in Photos still takes space until it is emptied.
- Move old videos off the phone, to a computer, or to iCloud Photos with Optimise iPhone Storage turned on.
Where the space goes afterwards
Where recordings end up matters for the next one. The Camera app saves to Photos, and with iCloud Photos those videos count against your iCloud storage. NoLight keeps recordings inside the app and leaves them out of iCloud backup, because a long 4K session would swallow most backups. Save the ones you want to keep to Photos, which is free, or export them to Files with NoLight Pro.
Short answers
How big is a one-hour 1080p iPhone video? Usually a few gigabytes. Plan for up to about 7 GB to be safe.
How big is a one-hour 4K video? Several times that. Plan for up to about 22 GB.
How do I make iPhone videos smaller? Use the High Efficiency format, 1080p instead of 4K, and 30 fps instead of 60.