Phones never give you all the storage printed on the box. Pick a size and see what you actually get — then mix your real usage and watch it fit (or not) in real time.
Buy a "128 GB" phone and the storage screen shows something closer to 105–112 GB free out of the gate. Nothing is broken — it happens for two honest reasons, and every phone does it.
Manufacturers count storage in decimal gigabytes (1 GB = 1,000,000,000 bytes). Your phone's operating system counts in binary (1 GB = 1,073,741,824 bytes). Same chip, different ruler. So a 128 GB drive is only about 119 GB once the OS measures it — you lost roughly 7% before installing a single app.
iOS or Android, the system files, and the apps that ship with the phone take up real space — usually 12–20 GB depending on the phone and software version. Subtract that from the 119 GB and you land near the 100–110 GB this calculator shows.
| Size | Roughly usable | Best for |
|---|---|---|
| 64 GB | ~50 GB | Avoid in 2026 unless you live in the cloud and shoot almost nothing. |
| 128 GB | ~105 GB | Fine for average users who back photos up to the cloud. |
| 256 GB | ~225 GB | The comfortable sweet spot for most people who shoot photos and some video. |
| 512 GB | ~460 GB | Heavy 4K shooters, large offline music/podcast libraries, big game collections. |
| 1 TB | ~930 GB | Creators who keep everything on-device and never want to think about space. |
Honest take: for most people in 2026, 256 GB is the size you won't regret. 128 GB works if you lean on cloud backup; 64 GB is false economy.
The numbers use real-world averages, not best-case marketing figures. Photos assume ~3.5 MB each (modern HEIC/JPEG); songs ~5 MB; the average app ~100 MB and a big 3D game ~3 GB. Video uses per-minute rates close to what phones record in HEVC: roughly 65 MB/min for 1080p, 190 MB/min for 4K at 30fps, and 440 MB/min for 4K at 60fps. Usable space subtracts the binary-formatting loss plus a typical system reserve (~14 GB on iPhone, ~12 GB on Android). Your real files will vary — that's exactly why every assumption above is adjustable under "Advanced."
Two reasons stack up: the box measures storage in decimal GB while your phone measures in binary (that alone drops 128 to ~119), and then the operating system plus pre-installed apps take another 12–20 GB. What's left — around 100–112 GB — is what you can actually use.
For an average user who backs photos up to the cloud, yes. If you shoot 4K video, download a lot of offline music, or install large games, 256 GB is the more comfortable choice. Use the slider above to test your own habits.
About 190 MB per minute at 4K 30fps, and roughly 440 MB per minute at 4K 60fps. That's around 11 GB and 26 GB per hour respectively — 4K video is by far the fastest way to fill a phone.
Videos, by a wide margin. A single minute of 4K video can equal 50+ photos. If storage is tight, your camera roll's videos are almost always the first thing worth trimming.
It's close and depends on the model and software skin. iOS typically reserves a touch more for the system, while heavier Android skins (with lots of pre-installed apps) can claim a similar amount. The difference is usually a few GB, not a deciding factor.
Most modern flagships have no microSD slot, so on-device storage is fixed at purchase — pick carefully. You can always extend effective space with cloud storage, but anything you want available offline still counts against the phone.
Estimates are for planning only and will differ from your phone's exact figures. Built by CripsyWire — honest tech, no hype.
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