Understanding Data Storage Units: Bytes to Terabytes
Demystify data storage units and understand why your 1TB drive doesn't actually show 1TB of available space.
Use the Bytes ↔ KB/MB/GB/TB
Convert between data storage units
The Binary System
Computers process everything in binary, using only the digits 0 and 1. Because of this, memory and storage have traditionally been measured in powers of 2 rather than powers of 10. In the binary system, 1 kilobyte (or more precisely, 1 kibibyte) equals 1,024 bytes, not 1,000. One megabyte is 1,048,576 bytes (1,024 squared), and one gigabyte is 1,073,741,824 bytes (1,024 cubed). The International Electrotechnical Commission introduced the terms kibibyte (KiB), mebibyte (MiB), and gibibyte (GiB) in 1998 to distinguish binary-based units from decimal-based ones, but in everyday language, most people still just say kilobyte, megabyte, and gigabyte without specifying which counting system they mean.
The Marketing Discrepancy
Hard drive and SSD manufacturers use the decimal (base-10) definition of storage units: 1 GB equals exactly 1,000,000,000 bytes. Your operating system, however, typically uses the binary (base-2) definition: 1 GB equals 1,073,741,824 bytes. This mismatch is why a drive marketed as having 1 TB of capacity shows up as approximately 931 GB in your computer's file manager.
Practical Storage Reference
Having a sense of how much space common files take up helps you plan your storage needs.