Units
Why does my 128 GB phone have less space than 128 GB?
128 GBis still reported
iPhones report capacity in decimal, like the box. The missing space is the operating system and built-in apps.
On a phone the unit isn't the main cause. iPhones count in decimal, the same as the box, and a 128 GB iPhone still has far less than 128 GB free, because the operating system takes its share before you save anything.
Apple's iOS and macOS count storage in decimal units, so a 128 GB iPhone reports a capacity of 128 GB. The free space is smaller because iOS and its built-in apps and caches are stored on the same chip. How much they take depends on the model and iOS version: check Settings › General › iPhone Storage. Android phones also list 'System' storage separately. Phones that report in binary units would show 119.2.
The arithmetic
- 128 GB = 128,000,000,000 bytes (the maker's decimal count)
- 1 GiB = 1,024 × 1,024 × 1,024 = 1,073,741,824 bytes
- 128,000,000,000 ÷ 1,073,741,824 = 119.21 GiB
- The number looks 6.9 % smaller, with every byte still there
| Sold as | Windows shows | Looks smaller by |
|---|---|---|
| 16 GB | “14.9 GB” | 6.9 % |
| 32 GB | “29.8 GB” | 6.9 % |
| 64 GB | “59.6 GB” | 6.9 % |
| 128 GB | “119.2 GB” | 6.9 % |
| 256 GB | “238.4 GB” | 6.9 % |
| 512 GB | “476.8 GB” | 6.9 % |
| 1 TB | “931.3 GB” | 6.9 % |
| 2 TB | “1.81 TB” | 9.1 % |
| 4 TB | “3.63 TB” | 9.1 % |
| 8 TB | “7.27 TB” | 9.1 % |