International Electrotechnical Commission (
IEC) & SI approved.
International Standard IEC 60027-2
Regular Système International (SI) unit prefixes:
Factor Prefix Symbol Factor Prefix Symbol
101 deca da 10-1 deci d
102 hecto h 10-2 centi c
103 kilo k 10-3 milli m
106 mega M 10-6 micro µ
109 giga G 10-9 nano n
1012 tera T 10-12 pico p
1015 peta P 10-15 femto f
1018 exa E 10-18 atto a
1021 zetta Z 10-21 zepto z
1024 yotta Y 10-24 yocto y
Prefixes for binary multiples:
Factor Name Symbol Origin Derivation
210 kibi Ki kilobinary: (210)1 kilo: (103)1
220 mebi Mi megabinary: (210)2 mega: (103)2
230 gibi Gi gigabinary: (210)3 giga: (103)3
240 tebi Ti terabinary: (210)4 tera: (103)4
250 pebi Pi petabinary: (210)5 peta: (103)5
260 exbi Ei exabinary: (210)6 exa: (103)6
Examples and comparisons with SI prefixes:
one kibibit 1 Kibit = 210 bits = 1024 bits
one kilobit 1 kbit = 103 bits = 1000 bits
one mebibyte 1 MiB = 220 B = 1 048 576 B
one megabyte 1 MB = 106 B = 1 000 000 B
one gibibyte 1 GiB = 230 B = 1 073 741 824 B
one gigabyte 1 GB = 109 B = 1 000 000 000 B