Understanding metric units

The metric system uses three main units for measuring:

  • metres
  • grams
  • litres

Other units are based on these basic units but have a prefix in front. The prefix tells you how much bigger or smaller the unit is:

  • kilo- means \(\times 1,000\)
  • centi- means \(\div 100\)
  • milli- means \(\div 1,000\)

The table shows some of the most common units and their equivalents. Make sure you know these conversions.

Converting measurements
Length\[{1}~{km} = {1,000}~{m}\]\[{1}~{m} = {100}~{cm}\]\[{1}~{cm} = {10}~{mm}\]
Weight\[{1~tonne} = {1,000}~{kg}\]\[{1}~{kg} = {1,000}~{g}\]\[{1}~{g} = {1,000}~{mg}\]
Capacity\[{1}~{l} = {100}~{cl}\]\[{1}~{cl} = {10}~{ml}\]\[{1}~{l} = {1,000}~{ml}\]