Dual CameraVideo File Size Calculator
Work out how much storage a recording will take before you start filming, by resolution, frame rate and length, using Apple's own published capture rates.
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Estimated file size
1.7 GB
170 MB per minute of recording
Roughly how much you could record with this setting:
How to read the result
Video size is a function of bitrate × time. Bitrate is set by the resolution, the frame rate and the codec, so the three controls above are really just three ways of changing how many megabits per second the encoder is allowed to spend.
The per-minute figures come from Apple's published capture rates, the same ones listed under Settings → Camera → Record Video on iPhone. They describe High Efficiency (HEVC) recording, which is the default on every iPhone since the 7.
Storage per minute, at a glance
| Quality | Per minute | 10 minutes | 1 hour |
|---|---|---|---|
| 720p HD · 30 fps | 40 MB | 0.4 GB | 2.3 GB |
| 1080p HD · 30 fps | 60 MB | 0.6 GB | 3.5 GB |
| 1080p HD · 60 fps | 90 MB | 0.9 GB | 5.3 GB |
| 4K · 24 fps | 135 MB | 1.3 GB | 7.9 GB |
| 4K · 30 fps | 170 MB | 1.7 GB | 10.0 GB |
| 4K · 60 fps | 400 MB | 3.9 GB | 23.4 GB |
Two cameras do not mean two files
This is the question we get most often, and the answer is reassuring: recording the front and back camera simultaneously does not double your storage. Both views are composited into a single frame as you record, so a 4K dual-camera clip weighs the same as any other 4K clip of the same length.
What it does increase is heat and battery, because two capture pipelines are running at once. If you are planning a long take, the limiting factor is usually thermal, not storage; dropping from 4K to 1080p helps with both.
Why your real files may be larger
- Motion. Encoders describe the difference between frames. A locked-off shot of a wall compresses to almost nothing; a handheld shot of a crowd does not.
- Detail. Foliage, water, confetti and fine texture are expensive. Flat surfaces are cheap.
- HDR. Dolby Vision HDR adds roughly a third.
- Format. Most Compatible (H.264) produces files close to twice the size of High Efficiency for the same visual quality.
Before a long shoot
Check free space in Settings → General → iPhone Storage and leave headroom beyond the estimate, because iOS needs working space to finalise a recording, and a volume that fills mid-take can cost you the clip. If you are close to the limit, record 1080p rather than gambling on 4K.