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A nanosecond (ns) is an SI unit of time equal to one thousand-millionth of a second, (or one billionth of a second) that is, 1/1,000,000,000 of a second, or 10−9 seconds.

The word nanosecond is formed by the prefix nano and the second one is second a basic unit of time or a sixtieth of a minute.

A nanosecond is equal to 1000 picoseconds or ​11000 microsecond. Because the next SI unit is 1000 times larger, times of 10−8 and 10−7 seconds are typically expressed as tens or hundreds of nanoseconds.

Times of this granularity are commonly encountered in telecommunications, pulsed lasers and some areas of electronics.

Common measurements[edit]

  • 0.5 nanoseconds – the half-life of beryllium-13.
  • 0.96 nanoseconds – 100 Gigabit Ethernet Interpacket gap
  • 1.0 nanosecond – cycle time of an electromagnetic wave with a frequency of 1 GHz (1×109 hertz).
  • 1.0 nanosecond – electromagnetic wavelength of 1 light-nanosecond. Equivalent to 0.3m radio band.
  • 1.016703362164 nanoseconds (by definition) – time taken by light to travel 1 foot in a vacuum.[n 1]
  • 1.1 nanoseconds – a commonly-used rough definition of a "light-foot".cf. [1][2]
  • 3.3356409519815 nanoseconds (by definition) – time taken by light to travel 1 metre in a vacuum.[3]
  • 10 nanoseconds – one "shake", (as in a "shake of a lamb's tail") approximate time of one generation of a nuclear chain reaction with fast neutrons
  • 10 nanoseconds – cycle time for frequency 100 MHz (1×108 hertz), radio wavelength 3 m (VHF, FM band)
  • 12 nanoseconds – mean lifetime of a K meson[4]
  • 10 nanoseconds – half-life of lithium-12
  • 20–40 nanoseconds – time of fusion reaction in a hydrogen bomb
  • 30 nanoseconds – half-life of carbon-21
  • 77 nanoseconds – a sixth (a 60th of a 60th of a 60th of a 60th of a second)
  • 96 nanoseconds – Gigabit Ethernet Interpacket gap
  • 100 nanoseconds – cycle time for frequency 10 MHz, radio wavelength 30 m (shortwave)
  • 299 nanoseconds – half-life of polonium-212
  • 286 nanoseconds – 1 Tstate of a Z80A microprocessor in a ZX Spectrum giving 3.5 MHz to the device clock.
  • 333 nanoseconds – cycle time of highest medium wave radio frequency, 3 MHz
  • 500 nanoseconds – T1 time of Josephson phase qubit (see also Qubit) as of May 2005
  • 1000 nanoseconds – one microsecond

See also[edit]


  1. ^ By definition of the "foot" as exactly 1/3 yards, and of the international yard as "exactly 0.9144 metres", and of the metre (SI unit) defined by the International Bureau of Weights and Measures as the "length of the path traveled by light in vacuum during a time interval of 1/299792458 of a second". The time taken by light to travel 1 foot in a vacuum is therefore (1/299792458)x(0.9144/3) seconds, or 1.016703362164 nanoseconds.
  1. ^ David Mermin (2009). It's About Time: Understanding Einstein's Relativity. Princeton, New Jersey: Princeton University Press. p. 22. ISBN 978-0-691-14127-5. 
  2. ^ Gamow, George (1961), One, Two, Three... Infinity: Facts & Speculations of Science (3rd ed.), Courier Dover Publications, p. 77, ISBN 0486256642 .
  3. ^ "Official BIPM definition of the metre". BIPM. Retrieved 2008-09-22. 
  4. ^  Missing or empty |title= (help); External link in |website= (help);