A single minute of 1080p video at the normal 30 fps will take only 130MB of space, which isn’t that bad. But if you do the same with 4K at the same frame rate, you’re looking at a whopping 375MB of storage.
That means if you’re eyeing the 16 GB iPhone, you’re probably going to want to turn your video size down. At that rate, you’d fill up a full 16 GB in about 40 minutes, and that’s not counting the space that’s already used up by iOS, apps, other photos and videos, music, and all of your other data.
Users on larger iPhones, like the 64 GB model, will have a little more room to stash those videos. The mid-size phone can store around three hours of footage. As you might already have guessed, the 128 GB phone can take about 6 hours of 4K video before running out of space.
Of course, all of these numbers are just estimates. Each minute of video may not take up exactly 375 MB, and available space on your phone will be less than the advertised 64 or 128 GB once the operating system is installed and all of your other data has been added. Still, these numbers should help give you a good idea of which model you’ll need depending on your video recording needs.