Convert digital storage between bits and bytes, with separate decimal and binary prefixes. Select GB or GiB explicitly instead of relying on an ambiguous meaning of gigabyte.
How to use this calculator
Enter the amount, choose the unit shown by the device or software, and choose the target. The equivalence table shows all supported decimal and binary units through exabytes and exbibytes. Scientific notation keeps very small ratios visible instead of rounding them to zero.
GB and GiB describe different quantities
A byte contains eight bits. Decimal prefixes increase by factors of 1,000; binary prefixes increase by factors of 1,024. Consequently, MB means 1,000,000 bytes while MiB means 1,048,576 bytes. Uppercase B means bytes; the bit options are written out to reduce ambiguity.
A storage device advertised in decimal units may display a smaller number in software that uses binary units. That numerical difference is not itself evidence of missing capacity. Formatting, filesystem metadata, recovery partitions, and reserved space can also change usable capacity; those effects are not calculated here.
Examples
Decimal storage shown in binary units
500 GB ≈ 465.6612873 GiB before accounting for any reserved space. Reversing those units converts the displayed amount back to decimal gigabytes.
A memory-size comparison
1 MiB = 1.048576 MB = 8,388,608 bits. The extra i in MiB identifies a binary multiple.
Formula
target amount = source amount × bits per source unit / bits per target unit
1 B = 8 bits
1 GB = 1,000,000,000 B
1 GiB = 1,073,741,824 B
Precision and interpretation
Amounts are numerical conversions, not an allocation model: fractional bits can appear when converting fractional inputs. Results use floating-point arithmetic with up to 12 significant digits, so this is not an exact large-integer file-counter tool. Select enough digits for your purpose without assuming the source measurement has that precision.
Definitions and further reading
Unit and quantity reference provides the underlying definitions. The examples above are worked calculations for this tool.