Orders of magnitude

An order of magnitude is a difference between two numbers equal to multiplying one of them by ten. Orders of magnitude are quite easily and commonly described through the use of scientific notation and powers of ten.

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 length, area, volume, or mass. This is useful for getting an intuitive sense of the comparative size of things and the overall scale of the universe.

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 cubes and the area of one face, mass of some water and its volume.

Time	Length	Area	Volume	Mass	Energy
10-44 s	10-35 m
...
[10-28 s]?	[10-19 m]?
[10-27 s]?	[10-18 m]?
[10-26 s]?	[10-17 m]?
[10-25 s]?	[10-16 m]?
[10-24 s]?	10-15 m
[10-23 s]?	[10-14 m]?
[10-22 s]?	10-13 m
[10-21 s]?	[10-12 m]?			[10-33 kg]? [10-32 kg]? 10-31 kg	[1000 eV]? [104 eV]? 105 eV
[10-20 s]?	10-11 m			[10-30 kg]? [10-29 kg]? [10-28 kg]?	1 MeV [10 MeV]? [100 MeV]?
[10-19 s]?	0.1 nm	[10-20 m2]? [10-19 m2]?		10-27 kg [10-26 kg]? [10-25 kg]?
[10-18 s]?	1 nm	[10-18 m2]? [10-17 m2]?		[10-24 kg]? [10-23 kg]? [10-22 kg]?
[10-17 s]?	10 nm	[10-16 m2]? [10-15 m2]?		[10-21 kg]? [10-20 kg]? 10-19 kg
[10-16 s]?	100 nm	[10-14 m2]? [10-13 m2]?	[10-21 m3]? [10-20 m3]? [10-19 m3]?	[10-18 kg]? [10-17 kg]? [10-16 kg]?	[0.1 J]? [1 J]? [10 J]?
[1 fs]?	1 μm	[10-12 m2]? [10-11 m2]?	[10-18 m3]? [10-17 m3]? [10-16 m3]?	[10-15 kg]? [10-14 kg]? [10-13 kg]?	[100 J]? [1000 J]? [104 J]?
[10 fs]?	10 μm	[10-10 m2]? [10-9 m2]?	[10-15 m3]? [10-14 m3]? [10-13 m3]?	[10-12 kg]? [10-11 kg]? [10-10 kg]?
[100 fs]?	100 μm	[10-8 m2]? [10-7 m2]?	[10-12 m3]? [10-11 m3]? [10-10 m3]?	[10-9 kg]? [10-8 kg]? [10-7 kg]?
[1 ps]?	1 mm	[10-6 m2]? [10-5 m2]?	[10-9 m3]? [10-8 m3]? [10-7 m3]?	[10-6 kg]? [10-5 kg]? [10-4 kg]?
[10 ps]?	1 cm	[1 cm2]? [10 cm2]?	[1 ml]? 10 ml 100 ml	[1 g]? 10 g 100 g
[100 ps]?	100 cm	0.01 m2 0.1 m2	1 l 10 l 100 l	[1 kg]? [10 kg]? 100 kg
1 ns	1 m	1 m2 10 m2	1 m3 [10 m3]? [100 m3]?	1 t [10 t]? [100 t]?
10 ns	10 m	100 m2 1,000 m2	[1,000 m3]? [10,000 m3]? [105 m3]?	[106 kg]? [107 kg]? [108 kg]?
100 ns	100 m	1 ha 10 ha	[106 m3]? [107 m3]? [108 m3]?	[109 kg]? [1010 kg]? [1011 kg]?
1 μs	1 km	1 km2 10 km2	[1 km3]? [10 km3]? [100 km3]?	[1012 kg]? [1013 kg]? [1014 kg]?
10 μs	10 km	108 m2 109 m2	[1012 m3]? [1013 m3]? [1014 m3]?	[1015 kg]? [1016 kg]? [1017 kg]?
100 μs	100 km	1010 m2 1011 m2	[1015 m3]? [1016 m3]? [1017 m3]?	[1018 kg]? [1019 kg]? [1020 kg]?
1 ms	1000 km	1012 m2 1013 m2	[1018 m3]? [1019 m3]? [1020 m3]?
10 ms	104 km	1014 m2 1015 m2
100 ms	105 km	1016 m2 1017 m2
1 s	106 km	1018 m2 [1019 m2]?
10 s	107 km	[1020 m2]? [1021 m2]?
100 s	1 AU
1 hr	10 AU
10 hr	100 AU
1 day	1000 AU
10 day	104 AU
1 yr	1 LY
10 yr	10 LY
100 yr	100 LY
1000 yr	1000 LY
104 yr	104 LY
105 yr	[105 LY]?
106 yr	[106 LY]?
107 yr	[107 LY]?
108 yr	[108 LY]?
109 yr	[109 LY]?
1010 yr	1010 LY
...
1031 yr

Units used in the table:

• Time: femtosecond? (fs), nanosecond? (ns), microsecond?, (μs), millisecond? (ms), second (m), hour (hr), day (dy), year (yr)
• Length: nanometre (nm), micrometre (μm), millimetre? (mm), centimetre? (cm), metre (m), kilometre? (km), astronomical unit (AU), light year (LY)
• Area: square metre (m²), hectare? (ha), square kilometre? (km²)
• Mass: gram (g), kilogram (kg), tonne (t)
• Volume: millilitre? (ml), litre (l), cubic metre (m³)
• Energy: electronvolt? (eV), Joule (J)

See also: SI units, SI prefix, conversion of units

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