Digital Storage Converter

The Digital Storage Converter expresses a byte quantity in decimal storage units or IEC binary units. Decimal KB, MB, GB, and TB use powers of 1,000. Binary KiB, MiB, GiB, and TiB use powers of 1,024. The distinct labels prevent a result based on one convention from being presented as the other.

Choose the unit shown by your file, device, operating system, or specification. The converter first changes the input to bytes and then divides by the target unit’s byte factor:

$\text{bytes} = \text{input} \times \text{source factor}$

$\text{target value} = \frac{\text{bytes}}{\text{target factor}}$

Keep decimal and binary labels distinct

Choose the unit exactly as the source reports it, distinguishing GB from GiB and MB from MiB. Compare both representations of the same amount rather than calling one missing storage. If reconciling a device’s advertised capacity with available space, note formatting and reserved space separately. The unit conversion alone cannot explain every difference between nominal capacity and usable space.

For reconciling two displays, work in this order:

1. Copy the exact original unit, including an IEC prefix when present.
2. Convert the same quantity into the comparison unit.
3. Compare the byte basis, then investigate compression, allocation, or reserved space separately.

A label convention and usable-space difference are different questions. The unit calculator answers the first; a device or filesystem record is needed to investigate the second.

Decimal storage units

The SI prefixes are decimal:

With the default units, 1 GB = 1,000 MB.

IEC binary storage units

IEC binary prefixes name powers of 1,024:

For example, 1 GiB = 1,024 MiB. Converting 1 GB to GiB instead gives approximately 0.931323 GiB because the byte factors differ.

If you need a transfer-rate conversion, use the data transfer rate converter. For base notation rather than storage units, use the binary converter.

Sources

• NIST, Metric SI prefixes — “SI Prefix Definitions” table: kilo is 10^3, mega 10^6, giga 10^9, and tera 10^12.
• IEC, Prefixes for binary multiples — table defining Ki, Mi, Gi, and Ti as 2^10, 2^20, 2^30, and 2^40.
• NIST, SP 800-88 Rev. 1, Appendix A — glossary entry defining a byte as a group of eight bits.