The following units of measure are used to define digital capacities and speeds. For measurements of a meter, see
metric system. See
binary values,
NIST binary and
long scale.
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Bits or Bytes Power of 10:
Kilo (K) Thousand 3
Mega (M) Million 6
Giga (G) Billion 9
Tera (T) Trillion 12
Bytes
Peta (P) Quadrillion 15
Exa (E) Quintillion 18
Zetta (Z) Sextillion 21
Yotta (Y) Septillion 24
Bronto Octillion 27
Geop Nonillion 30
Storage Capacity Measured in:
CPU word size bits
Disk/SSD/USB drive bytes
Memory (RAM) bytes
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Fractions of
One Second Power of 10:
Millisecond (ms) Thousandth -3
Microsecond (µs) Millionth -6
Nanosecond (ns) Billionth -9
Picosecond (ps) Trillionth -12
Femtosecond (fs) Quadrillionth -15
Attosecond (as) Quintillionth -18
Zeptosecond (zs) Sextillionth -21
Yoctosecond (ys) Septillionth -24
Transmit/Transfer Measured in:
Cellular data total bytes
Parallel bus/channel bytes/sec
Disk/solid state drive bytes/sec
Memory (RAM) bytes/sec
PCI Express bus bytes/sec
USB bits/sec
Network/communications bits/sec
Disk access time ms
SSD access time µs
RAM access time ns
Machine cycle µs, ns
Instruction execution µs, ns
Transistor switching ns, ps, fs
CPU Speed - Clock Cycles Per Second
1 cycle/sec = 1 Hertz See Hertz.
kilohertz (kHz) thousand
megahertz (MHz) million
gigahertz (GHz) billion