Data Storage Converter

KB (kilobyte) is decimal: 1 KB = 1,000 bytes. KiB (kibibyte) is binary: 1 KiB = 1,024 bytes. The decimal prefixes (k, M, G, T, P) follow the SI standard. The binary prefixes (Ki, Mi, Gi, Ti, Pi) were standardized by IEC in 1998 to disambiguate. The gap grows: 1 TiB ≈ 1.0995 TB.

It depends. Windows historically displays binary sizes labeled as KB/MB/GB (so a '500 GB drive' shows about 465 GB free in Windows). macOS since 10.6 (2009) displays decimal sizes that match the drive label. Linux varies by tool. Storage manufacturers always use decimal: a 1 TB drive is 1,000,000,000,000 bytes.

Manufacturers count in decimal (1 TB = 10^12 bytes). Many file managers count in binary (1 GiB = 2^30 bytes) but label the result 'GB'. So 10^12 bytes shows as 10^12 ÷ 2^30 ≈ 931 binary 'GB'. The drive isn't smaller than advertised; the units are inconsistent.

Probably not for everyday questions. If you're comparing what you bought to what you see, the decimal-to-binary difference is the explanation. For programming or systems work where exact byte counts matter, use the binary units (KiB, MiB, GiB) explicitly.

Lowercase 'b' is bits, not bytes. 1 byte = 8 bits. Internet speeds are usually quoted in Mb/s (megabits per second), so a 100 Mb/s connection transfers about 12.5 MB/s (megabytes per second). This calculator handles bytes, not bits. Divide by 8 if you have bits.

They exist (EB, ZB, YB and their binary counterparts EiB, ZiB, YiB), but they are well beyond consumer-scale data. The calculator stops at petabytes to keep the unit list focused. Multiply by 1,000 for each step up: 1 EB = 1,000 PB, 1 ZB = 1,000 EB, etc.