Capacity (sometimes referred to as volume) is a measurement of how much space something takes up.
When you buy milk, how much is in each bottle or carton? What about when you buy juice?
Most people buy milk in cartons or bottles of one, two, four or six pints. Juice is usually sold in cartons or bottles of one litre.
Pints are an imperial measure of volume, and litres are a metric measure of volume. A litre is slightly less than two pints. We are going to focus on metric units here.
You sometimes see capacity marked in centilitres (cl), such as on the side of a bottle of water, where the measurement may be shown as 50 cl or 500 ml. However, the most common metric units of capacity are millilitres and litres, so these are what we will focus on here.
Key fact: One litre (1 l) is the same as 1 000 millilitres (1 000 ml).