Binary Prefixes

From HwB

SI Prefixes are not used in the computer world, things are a bit different:

Contents

Commonly used

These prefixes are easily confused with SI Prefixes.

Symbol Prefix Factor Factor
P peta 250 1125899906842624
T tera 240 1099511627776
G giga 230 1073741824
M Mega 220 1048576
k kilo 210 1024

IEC 60027-2 / IEEE 1541-2002

IEC has adopted these prefixes to solve the confusion. These are not widely used (yet).

Symbol Prefix Factor Factor
Yi yobi 280 1208925819614629174706176
Zi zebi 270 1180591620717411303424
Ei exbi 260 1152921504606846976
Pi pebi 250 1125899906842624
Ti tebi 240 1099511627776
Gi gibi 230 1073741824
Mi mebi 220 1048576
Ki kibi 210 1024

kibi originates from kilobinary

Bits/Bytes

Symbol Suffix Description
b bit one binary digit, value 0 or 1
B Byte 4-10 bits, but in most cases 8 bits
o octet 8 bits

Examples

Symbol Prefix
1 kB 1024 bytes (but 1000 bytes according to SI)
1 KiB 1024 bytes (IEC)
10 Mb/s 10485760 bits/second = 1310720 bytes/second (but 1250000 bytes/seconds according to SI)
10 Mib/s 10485760 bits/second = 1310720 bytes/second (IEC)

Standards

  • IEC 60027-2:2005
  • IEEE 1541-2002

See also

Contributions

Sources