Orders of magnitude (original) (raw)

An order of magnitude is a factor of ten. For example, two numbers are said to differ by "3 orders of magnitude" if one is 1000 times larger than other. Orders of magnitude are quite easily and commonly described through the use of scientific notation and powers of ten. An order of magnitude estimate is not concerned with the precise value, but instead with the number of decimal digits after the first. It can also be called a zeroth order approximation.

One way of categorising things in the physical world is by their size. The pages below contain lists of items that are of the same order of magnitude in time, length, area, volume, mass, or energy. This is useful for getting an intuitive sense of the comparative size of things and the overall scale of the universe. SI units are used together with SI prefixes: these were devised with orders of magnitude in mind. Each individual page also gives other units; see also conversion of units.

In the following table the different quantities are lined up so that the following are in the same row: length and the time taken by light to cross that length, area of a square and the length of one side, volume of a cube and the area of one face, mass of some water and its volume. See also the separate tables for length, area, volume, mass, time and dimensionless numbers.

Time Length Area Volume Mass Energy Temperature
(second) (metre) (square metre) (cubic metre) (kilogram) (joule) (kelvin)
10-44 s 10-35 m
...
10-28 s 100 zm
10-27 s 1 am 1 nK
10-26 s 10 am 1 peV 1 µK
10-25 s 100 am 1 mK
10-24 s 1 fm 0.001 meV 0.01 meV 0.1 meV 1 K
10-23 s 10 fm 1 meV 10 meV 100 meV 10 K 100 K 1000 K
10-22 s 100 fm 10-28 m2 1 eV 10 eV 100 eV 10,000 K 100,000 K 106 K
10-21 s 1 pm 10-33 kg 10-32 kg 10-31 kg 1000 eV 104 eV 105 eV 109 K
10-20 s 10pm 10-30 kg 10-29 kg 10-28 kg 1 MeV 10 MeV 100 MeV 109 K
10-20 s 10pm 10-30 kg 10-29 kg 10-28 kg 1 MeV 10 MeV 100 MeV 1012 K
10-19 s 100 pm 10-20 m210-19 m2 10-27 kg 10-26 kg 10-25 kg 1 GeV 10 GeV 100 GeV 1015 K
10-18 s 1 nm 10-18 m210-17 m2 10-24 kg 10-23 kg 10-22 kg 1 TeV 10 TeV 100 TeV 1018 K
10-17 s 10 nm 10-16 m210-15 m2 10-21 kg 10-20 kg 10-19 kg 0.0001 J 0.001 J 0.01 J 1021 K
10-16 s 100 nm 10-14 m210-13 m2 10-21 m310-20 m310-19 m3 10-18 kg 10-17 kg 10-16 kg 0.1 J 1 J 10 J 1024 K
1 fs 1 μm 10-12 m210-11 m2 10-18 m310-17 m310-16 m3 10-15 kg 10-14 kg 10-13 kg 100 J 1000 J 10000 J 1027 K
10 fs 10 μm 10-10 m210-9 m2 10-15 m310-14 m310-13 m3 10-12 kg 10-11 kg 10-10 kg 100000 J 0.001 kWh 0.01 kWh 1030 K
100 fs 100 μm 10-8 m210-7 m2 10-12 m310-11 m310-10 m3 10-9 kg 10-8 kg 10-7 kg 0.1 kWh 1 kWh 10 kWh
1 ps 1 mm 10-6 m210-5 m2 10-9 m310-8 m310-7 m3 10-6 kg 10-5 kg 10-4 kg 100 kWh 1000 kWh 10000 kWh
10 ps 1 cm 1 cm210 cm2 1 ml10 ml100 ml 1 g 10 g 100 g 100000 kWh 1 TWh 10 TWh
100 ps 10 cm 0.01 m20.1 m2 1 l10 l100 l 1 kg 10 kg 100 kg 100 TWh 1000 TWh 10000 TWh
1 ns 1 m 1 m210 m2 1 m310 m3100 m3 1 t 10 t 100 t 100000 TWh 106 TWh 107 TWh
10 ns 10 m 100 m21,000 m2 1,000 m310,000 m3 105 m3 106 kg 107 kg 108 kg 108 TWh 109 TWh
100 ns 100 m 1 ha10 ha 106 m3 107 m3 108 m3 109 kg 1010 kg 1011 kg 1012 TWh
1 μs 1 km 1 km210 km2 1 km3 10 km3 100 km3 1012 kg 1013 kg 1014 kg 1015 TWh
10 μs 10 km 108 m2109 m2 1012 m3 1015 kg 1016 kg 1017 kg 1018 TWh
100 μs 100 km 1010 m21011 m2 1015 m3 1018 kg 1019 kg 1020 kg 1021 TWh
1 ms 1000 km 1012 m21013 m2 1018 m3 1021 kg 1022 kg 1023 kg 1024 TWh
10 ms 104 km 1014 m21015 m2 1021 m3 1024 kg 1027 TWh
100 ms 105 km 1016 m21017 m2 1024 m3 1027 kg 1030 TWh
1 s 106 km 1018 m21019 m2 1027 m3 1030 kg 1033 TWh
10 s 107 km 1020 m21021 m2 1033 kg 1036 TWh
100 s 1 AU 1036 kg 1039 TWh
1 hr 10 AU 1039 kg 1042 TWh
10 hr 100 AU 1042 kg 1045 TWh
1 day 1000 AU 1045 kg 1048 TWh
10 day 104 AU 1048 kg 1051 TWh
1 yr 1 LY 1051 kg 1054 TWh
10 yr 10 LY
100 yr 100 LY
1000 yr 1000 LY
104 yr 104 LY 1040 m21041 m2
105 yr 105 LY
106 yr 106 LY
107 yr 107 LY
108 yr 108 LY
109 yr 109 LY
1010 yr 1010 LY
1011 yr
1012 yr and more

Units used in the table

The table uses units and prefixes that are commonly recognized:

See also