1 GB is equal to

Concept: Digital storage is counted in bytes, and one byte is a group of 8 bits. Memory-capacity prefixes follow the binary convention, in which every step up the ladder multiplies by 210 = 1024. On that ladder the kilo step is 210, the mega step is 220 and the giga step is 230 of the base unit.

Application: Build the giga step up from a single byte, one prefix at a time.

1. 1 KB = 1024 bytes = 210 bytes.

2. 1 MB = 1024 KB = 210 × 210 bytes = 220 bytes.

3. 1 GB = 1024 MB = 210 × 220 bytes = 230 bytes.

Cross-check: Two checks fix the reading. The unit has to be the byte and not the bit, because the same capacity expressed in bits is eight times larger: 23 × 230 = 233 bits. And 220 bytes sits one prefix step lower on the same ladder, at the mega step rather than the giga step.

Note on conventions: The IEC/NIST standard reserves GB for the decimal quantity 109 bytes and names the binary quantity 230 bytes a gibibyte (GiB). Memory-capacity questions in this exam, and this option set, use the older binary convention in which GB denotes 230 bytes; none of the offered values equals 109 bytes.

Result: 1 GB = 230 bytes = 1024 MB = 1,073,741,824 bytes.