Why a 1 TB drive shows 931 GB
Drive makers count in decimal, so 1 TB is 1,000,000,000,000 bytes. Windows divides by powers of 1,024 and still labels the result GB, so the same drive appears as about 931 GB. Nothing is missing; the two numbers use different units. To tell them apart, the IEC named the binary units KiB, MiB, GiB and TiB.
- 1 KB = 1,000 bytes, 1 KiB = 1,024 bytes
- 1 GB = 1,000 MB, 1 GiB = 1,024 MiB
- 1 byte = 8 bits