Room for ChanceWhat it measures and where it is used
Digital storage counts information units. A byte contains eight bits. Decimal kB, MB and GB use powers of 1,000; binary KiB, MiB and GiB use powers of 1,024. IEC binary prefixes were introduced to resolve this long-standing ambiguity in computing.
- Classification
- Information quantity; bit and byte are not SI units
- SI unit
- —
- Dimension
- 1
L: length; M: mass; T: time; Θ: temperature; N: amount of substance. The dimension symbol N is not the unit symbol for newton.
How it works
The calculation first converts to a common reference unit, then to the destination unit. Factors in the table show the reference value for one unit.
Example
1 KiB ≈ 1,024 B
Available units
Reference unit: B
| Available units | Reference factor |
|---|---|
| B | 1 × x |
| bit | 0.125 × x |
| kB | 1,000 × x |
| MB | 1,000,000 × x |
| GB | 1,000,000,000 × x |
| TB | 1,000,000,000,000 × x |
| PB | 1,000,000,000,000,000 × x |
| KiB | 1,024 × x |
| MiB | 1,048,576 × x |
| GiB | 1,073,741,824 × x |
| TiB | 1,099,511,627,780 × x |
Units, history and conventions
The International System of Units (SI) received its name in 1960. Since the 2019 revision, its definitions use fixed values of seven defining constants. SI base and derived quantities should not be confused with the different units used to express them.