Mass and Capacity
Section: Measurement | Syllabus: Cambridge Primary Mathematics (0845)
Capacity and Volume
Capacity and volume are closely related but different measurements. Capacity is how much a container can hold, while volume is the amount of space something takes up.
- Capacity is the maximum amount a container can hold - it only applies to hollow objects like bottles, jugs or tanks
- Volume is the amount of 3D space an object takes up - every solid or hollow object has a volume, whether or not it can hold anything
- Capacity is usually measured in millilitres (ml) and litres (l); volume is usually measured in cubic units like cm³ and m³
- 1 cm³ of liquid takes up the same space as 1 ml, so the two sets of units are directly linked: 1 litre = 1000 cm³
The jug's capacity is how much it can hold; the cube's volume is how much space it takes up
Worked Example: Distinguishing Capacity from Volume
- Question: A water tank can hold up to 200 litres when full, but currently has 120 litres of water in it. What is the tank's capacity, and what is the volume of water currently inside it?
- Step 1: Capacity is the maximum the container can hold: 200 litres
- Step 2: Volume, here, is the actual amount of space the water takes up right now: 120 litres
- Answer: Capacity = 200 litres, volume of water = 120 litres
Common Mistakes
MistakeThinking capacity and volume always mean the same amount
Fixcapacity is the maximum a container could hold; the volume of what is actually inside can be less than the full capacity
MistakeUsing "capacity" to describe a solid object that cannot hold anything
Fixsolid objects have volume (the space they take up) but not capacity, since they have nothing to hold
Interactive revision notes, videos and practice questions load below.