Data Storage Converter
Convert between bytes, KB/MB/GB/TB/PB (SI decimal) and KiB/MiB/GiB/TiB/PiB (IEC binary), plus bit-rates — live, with every unit on screen.
Data storage converter
SI decimal · 1 KB = 1,000 BReal-world scale
Approximate equivalents for your inputSI vs IEC — the 1,000 vs 1,024 split
The drift grows as units get larger| Unit | SI (decimal) | IEC (binary) | Drift |
|---|---|---|---|
| Kilo (K) | 1.000 | 1.024 | +2,4 % |
| Mega (M) | 1.000.000 | 1.048.576 | +4,9 % |
| Giga (G) | 1.000.000.000 | 1.073.741.824 | +7,4 % |
| Tera (T) | 1012 | 240 | +10,0 % |
| Peta (P) | 1015 | 250 | +12,6 % |
IEC units (KiB, MiB, GiB…) were introduced in 1998 to remove the ambiguity of "kilobyte" meaning either 1,000 or 1,024 bytes. Today, SI units (KB, MB, GB) are the formal standard for decimal quantities, while IEC units (KiB, MiB, GiB) are reserved for binary, power-of-2 quantities used in memory addressing and file sizes reported by most operating systems.
Why does a 1 TB drive show up as 931 GB?
Short answer: marketing uses SI, your OS uses IECHard-drive and SSD manufacturers label capacity using SI decimal units — a "1 TB" drive holds exactly 1,000,000,000,000 bytes (1012). Most operating systems (Windows, Linux file managers, older macOS) report that same byte count in IEC binary units, where 1 TiB = 1,099,511,627,776 bytes (240).
Nothing is missing — it's the same byte count, just displayed with a smaller divisor. macOS switched to decimal reporting in 10.6 (2009), so a 1 TB drive shows up as ~1.0 TB there. Windows and most Linux tools still use binary reporting but mislabel it as "GB" rather than "GiB", which is the root of the confusion.