Converting from one metric unit to another

Perhaps the most common metric conversions are between mm, cm, m and km.

1 cm = 10 mm

1 m = 100 cm = 1000 mm

1 km = 1000 m = 100 000 cm = 1 000 000 mm

kilo means 1000, so 1 km = 1000 m

centi means ¹/₁₀₀^th, so 1 cm = ¹/₁₀₀^th m

milli means ¹/₁₀₀₀^th, so 1 mm = ¹/₁₀₀₀^th m

Converting units of mass and capacity

Once you are confident with conversions between mm, cm, m and km, converting units of mass and capacity is eaier.

For example:

1 km = 1000 m, so 1 kg = 1000 g

1 m = 100 cm, so 1 l (litre) = 100 cl (centilitres)

1 m = 1000 mm, so 1 g = 1000 mg (milligrams)