isr.co.ro : glossary Gigabyte (GB) Literally, a billion (1,000,000,000) bytes. In most computer contexts, each thousand is replaced by a binary thousand equal to 1024, which is 2 to the 10th power, so a gigabit is usually taken as 1024 x 1024 x 1024 or 1,073,741,824. However, some disk-drive makers use the smaller exact decimal value in order to claim a larger number of gigabytes of disk capacity.