# 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
10-31 kg
1000 eV
105 eV
10-20 s 10-11 m 10-30 kg
10-28 kg
1 MeV
100 MeV
10-19 s 0.1 nm 10-20 m2
10-19 m2
10-27 kg
10-25 kg
10-18 s 1 nm 10-18 m2
10-17 m2
10-24 kg
10-22 kg
10-17 s 10 nm 10-16 m2
10-15 m2
10-21 kg
10-19 kg
10-16 s 100 nm 10-14 m2
10-13 m2
10-21 m3
10-19 m3
10-18 kg
10-16 kg
0.1 J
10 J
1 fs 1 μm 10-12 m2
10-11 m2
10-18 m3
10-16 m3
10-15 kg
10-13 kg
100 J
104 J
10 fs 10 μm 10-10 m2
10-9 m2
10-15 m3
10-13 m3
10-12 kg
10-10 kg
100 fs 100 μm 10-8 m2
10-7 m2
10-12 m3
10-10 m3
10-9 kg
10-7 kg
1 ps 1 mm 10-6 m2
10-5 m2
10-9 m3
10-7 m3
10-6 kg
10-4 kg
10 ps 1 cm 1 cm2
10 cm2
1 ml
100 ml
1 g
100 g
100 ps 100 cm 0.01 m2
0.1 m2
1 l
100 l
1 kg
100 kg
1 ns 1 m 1 m2
10 m2
1 m3
100 m3
1 t
100 t
10 ns 10 m 100 m2
1,000 m2
1,000 m3
105 m3
106 kg
108 kg
100 ns 100 m 1 ha
10 ha
106 m3
108 m3
109 kg
1011 kg
1 μs 1 km 1 km2
10 km2
1 km3
100 km3
1012 kg
1014 kg
10 μs 10 km 108 m2
109 m2
1012 m3
1014 m3
1015 kg
1017 kg
100 μs 100 km 1010 m2
1011 m2
1015 m3
1017 m3
1018 kg
1020 kg
1 ms 1000 km 1012 m2
1013 m2
1018 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: