Audio payload bytes do not change when their display unit changes, but the visible number does. Storage manufacturers commonly label decimal gigabytes, while software may display binary gibibytes or label a binary value as GB. AudioSize keeps exact bytes as the source of truth and shows both families together.
Decimal storage follows powers of 1000
One kB is 1,000 bytes, one MB is 1,000,000, one GB is 1,000,000,000, and one TB is 1,000,000,000,000. A card sold as 32 GB supplies a nominal 32,000,000,000 bytes before formatting, reserved areas, wear management, and the recorder's own policies reduce usable capacity.
Binary storage follows powers of 1024
One KiB is 1,024 bytes, one MiB is 1,048,576, one GiB is 1,073,741,824, and one TiB is 1,099,511,627,776. The same 32,000,000,000 bytes are about 29.802 GiB, not because bytes disappeared but because the divisor is larger.
Reverse from bytes, not a rounded label
Recording time is derived from the capacity in bytes and whole PCM frames. Reusing a rounded GB or GiB display would compound rounding and could claim one frame too many. AudioSize keeps the entered decimal as a rational, floors it to physical bytes, then fits only complete frames.
Nominal capacity is not guaranteed free space
Formatting, filesystem structures, existing files, bad-block reserves, over-provisioning, recorder databases, pre-roll, safety tracks, and file splitting can reduce practical time. Enter the free capacity reported by the actual recorder when possible and keep an operational margin instead of planning to the final calculated frame.