KB vs KiB — why sizes never match
Decimal units (KB, MB, GB) use powers of 1000 and are what drive manufacturers advertise. Binary units (KiB, MiB, GiB) use powers of 1024 and are what operating systems often report. A "500 GB" drive is about 465 GiB — nothing is missing, the units just differ.
Rule of thumb
The gap grows with scale: ~2.4% at KB/KiB, ~4.9% at MB/MiB, ~7.4% at GB/GiB, and ~10% at TB/TiB.