Gigabyte (GB) Conversions
What Is a Gigabyte?
A gigabyte is just a convenient way to say "a billion bytes" without writing out ten digits every time. Once you're talking about an app install, a video file, or a chunk of cloud storage, counting in bytes — or even kilobytes — gets unreadable fast. A billion bytes is roughly what you'd need for a couple of photo albums shot at high resolution, a short HD video clip, or a modest piece of software.
Just like the megabyte, the gigabyte has its own decimal‑versus‑binary confusion. Storage companies use the decimal system, where a gigabyte is 1,000,000,000 bytes. Computers often use the binary system, where a “gigabyte” is really 1,073,741,824 bytes — about 7.4% more. That’s why a 1 TB drive shows up as around 931 GB on your computer. Nothing’s missing — it’s simply being measured differently.
A short history of the Gigabyte
"Giga-" comes from the Greek word for "giant," and became the official SI prefix for one billion in 1960. It stayed mostly theoretical in computing for a while — early machines worked in bytes and kilobytes, and it took decades for hard drives to actually reach that scale. One of the first was IBM's 3380 in 1980: fridge-sized, over $40,000, and about 2.5 GB.
As drives kept growing through the 80s and 90s, the gigabyte turned into the everyday unit for consumer storage — and it inherited the same decimal-vs-binary tug-of-war that had already been dogging the megabyte. Memory and operating systems stuck with the binary version (1,073,741,824 bytes), since that's how addressing naturally works, while drive manufacturers kept marketing capacity using the cleaner decimal figure of an even billion bytes.
When the IEC introduced its binary-prefix standard in 1998, the gigabyte got its own unambiguous label too — "GiB," short for gibibyte, meaning the binary 1,073,741,824-byte value — which freed up "GB" to mean the decimal billion. Adoption has been just as spotty as it was for the megabyte: storage and network specs mostly use decimal GB, but plenty of memory and OS contexts still quietly mean binary even while calling it "GB." Worth double-checking whenever the exact byte count actually matters.
Gigabyte Conversion Basics
Once you're anchored to bytes, the conversion is just simple arithmetic — convert your GB value to bytes, then divide by whatever the target unit's byte factor is. That two-step process works the same way no matter which unit you're converting to: get to bytes first, then scale from there.
Gigabyte Converter Links to Other File Size Units
Convert Gigabyte (GB) to any other supported unit: