Converting units

As a prescriber, you may encounter doses of medicines that are expressed in either grams, milligrams or micrograms or volumes of medicines that are expressed in litres, millilitres or occasionally microlitres when referring to a very small quantity, such as a small number of drops of liquid.

It is important to understand the relationship between these units of mass and volume. The examples in this article provides some practice in converting units. For the purpose of this drug calculation exercise, the standard international (SI) units used will relate to mass and volume:

To convert from larger to smaller units, multiply by 1000 for each step. To convert from smaller to larger, divide by 1000.