Storage units are notoriously ambiguous — a "1 TB" hard drive uses the SI definition (10¹² bytes) while your operating system reports it as 931 GB using the binary definition (2⁴⁰ bytes). This converter handles both SI (kilo/mega/giga/tera = powers of 1,000) and IEC (kibi/mebi/gibi/tebi = powers of 1,024) prefixes, making the "missing storage" mystery immediately clear.
The IEC 80000-13 standard introduced separate prefixes for binary multiples to end the confusion: kibibyte (KiB) = 1,024 bytes; mebibyte (MiB) = 1,048,576 bytes; gibibyte (GiB) = 1,073,741,824 bytes. Drive manufacturers use SI prefixes (KB = 1,000, MB = 1,000,000) because they give larger-seeming numbers. Operating systems traditionally used SI prefix names but IEC binary values — reporting a 1 TB (10¹² byte) drive as 931 GB (2³⁰ × 931 bytes). macOS switched to SI (base-10) reporting in 10.6 Snow Leopard; Windows still uses binary values with SI prefix names.
1 TB = 1,000,000,000,000 bytes (manufacturer). Windows reports in GiB (1,073,741,824 bytes each) but labels it "GB". So 1,000,000,000,000 ÷ 1,073,741,824 ≈ 931. No space is missing — it is a unit labelling difference.
A gibibyte (GiB) = 2³⁰ = 1,073,741,824 bytes. It is the IEC standard term for what was historically called a "gigabyte" in computing contexts. The SI gigabyte (GB) = 10⁹ = 1,000,000,000 bytes.
RAM is specified in binary units — a 16 GB RAM module is actually 16 GiB (2⁴ × 1,073,741,824 bytes). RAM manufacturers use binary prefixes consistently, unlike storage manufacturers.
Internet speeds are in megabits per second (Mbps). File sizes are in megabytes (MB). Divide Mbps by 8 to get MB/s download speed. A 100 Mbps connection downloads at ~12.5 MB/s; a 1 GB file takes ~80 seconds.
See also the Unit Converter for length/weight/temperature and the Binary to Decimal converter.