Generally, use abbreviations for units when they appear with numerals; spell out the units when they are used alone or when they are used with spelled-out numbers (see also 37f).
METRIC UNITS |
US STANDARD UNITS |
|---|---|
|
m, cm, mm |
yd, ft, in. |
|
km, kph |
mi, mph |
|
kg, g, mg |
lb, oz |
Results were measured in pounds.
Runners in the 5-km race had to contend with pouring rain.
Use no periods after abbreviations for units of measurement, except the abbreviation for “inch” (in.), to distinguish it from the preposition in.