Bytes, KB, MB and GB Explained (Data Sizes)
A KB is 1024 bytes, an MB is 1024 KB, and so on. Learn how digital storage units work and why file sizes never quite match the label on a drive.
Digital storage is measured in bytes, and each larger unit is 1024 of the one below it: 1 KB = 1024 bytes, 1 MB = 1024 KB, 1 GB = 1024 MB. A byte is 8 bits, enough to store one character.
The ladder of units
- 1 byte (B) = 8 bits
- 1 kilobyte (KB) = 1024 B
- 1 megabyte (MB) = 1024 KB
- 1 gigabyte (GB) = 1024 MB
- 1 terabyte (TB) = 1024 GB
Why a "1 TB" drive shows less
Storage makers often count in powers of 1000 (1 KB = 1000 B), while operating systems count in powers of 1024. So a drive sold as 1 TB (10¹² bytes) shows as about 931 GB in your computer — nothing is missing, just two different definitions.
Bits vs bytes
Internet speeds are quoted in bits per second (Mbps), while files are in bytes. Since a byte is 8 bits, a 100 Mbps connection downloads at roughly 12.5 MB/s.
Convert instantly
The unit converter converts between B, KB, MB, GB and TB with live updates. Sizing images for the web? See How to compress images for the web.