isr.co.ro : glossary Gigabit (Gb) Literally, a billion (1,000,000,000) bits. However, 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. So far, you're likely to run into the term in the number of bits per second transmitted across high-speed optical links.