About the Data Size Converter
The Data Size Converter handles both decimal units (KB = 1000 B, used by drive makers) and binary units (KiB = 1024 B, used by operating systems) — the reason a "1 TB" drive shows only ~931 "GB" in Windows.
The drive has 10^12 bytes (decimal TB); Windows displays binary GiB (2^30) but labels them GB — 10^12 ÷ 2^30 ≈ 931.