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measurement

Capacity in real life

Measure drinks, recipes, baths and containers.

Quick answer

Capacity is how much a container can hold, measured in litres, millilitres, cups, pints, or gallons.

Learning outcome

By the end of this page, you will be able to measure and compare how much different containers can hold using everyday units like litres and millilitres. Success signs:
  • You can tell which container holds more or less
  • You can use a measuring jug to find capacity
  • You can solve problems about filling containers
  • You can estimate how much a container holds before measuring

Why this matters

Capacity helps us understand how much liquid or dry goods fit in containers. You use capacity when:
  • Choosing the right-sized water bottle for school
  • Following a recipe that needs 250ml of milk
  • Deciding if a jug is big enough to fill a fish tank
  • Sharing drinks at a party
  • Planning how much water to take on a walk
Capacity is also useful in sports, cooking, science experiments, and building projects. Knowing capacity helps you be more confident when solving problems about how much things can hold.

How it works

Capacity is measured using units like:
  • Millilitres (ml) – used for small amounts like a sip of juice
  • Litres (l) – used for larger amounts like a bottle of water
To measure capacity:
  1. Choose a measuring container (like a jug or cup)
  2. Fill your container with water or another liquid
  3. Read the level on the measuring container
  4. Write down how much it holds
You can also compare containers by filling one with water and pouring it into another to see which holds more.

Examples you can see

Let’s look at some real containers and how much they can hold:
Container Estimated Capacity Actual Capacity
Teacup 250 ml 250 ml
Water bottle 500 ml 500 ml
Large jug 1 litre 1 litre
Bath 150 litres 150 litres
Small saucepan 500 ml 500 ml
You can also use these examples to compare capacity:
  • A teacup holds less than a water bottle
  • A large jug holds the same as a water bottle
  • A bath holds much more than a saucepan

Try it as a mini adventure

Adventure: The Water Wiz You are a water wizard who needs to fill containers for a magical party. Your magic bag has 3 different containers: a small cup, a medium jug, and a large bucket. You need to find out how much each holds. Step 1: Take a small cup and fill it with water from the tap. Pour the water into a measuring jug. You find it holds 200 ml. Step 2: Now fill the medium jug with water and pour it into the measuring jug. You find it holds 800 ml. Step 3: Finally, fill the large bucket and pour it into the measuring jug. It holds 4 litres. Step 4: Compare your containers. Which holds the most? Which holds the least? Step 5: Use your containers to pour water from one to another to see how they fit together. What happens when you pour the small cup into the large bucket? Step 6: Make a chart showing your results. Draw pictures of each container and write how much it holds.

Common mistakes

  • Mistake: Thinking that a tall container holds more than a short one, even if they are the same size.
    Why it happens: Children often confuse height with capacity.
    Fix: Use a measuring jug to check actual capacity instead of just looking at the shape.
  • Mistake: Mixing up millilitres and litres.
    Why it happens: The units look similar and are both used for measuring liquids.
    Fix: Remember that 1 litre = 1000 millilitres. Use a litre bottle to show how much that is.
  • Mistake: Guessing capacity without checking.
    Why it happens: It’s easier to guess than to measure.
    Fix: Always measure first, then guess again to see if you were close.

Parent and carer guide

As a parent or carer, you can help your child learn about capacity by:
  • Using everyday containers to measure and compare liquids
  • Letting your child pour water between containers to see how much fits
  • Asking questions like “Which holds more?” or “How much more do we need?”
  • Using a measuring jug to check guesses
  • Encouraging your child to estimate before measuring
  • Playing capacity games like “Guess the capacity” or “Fill it up”
It’s important to be patient. Capacity can be tricky for young children, so don’t worry if they don’t get it right away. Practice makes progress!

Practice questions

  1. How many millilitres are in 1 litre?
  2. Which holds more: a 500 ml bottle or a 1 litre bottle?
  3. If a teacup holds 200 ml and a jug holds 750 ml, how much more does the jug hold?
  4. How many 250 ml cups can you fill from a 1 litre bottle?
  5. Which would hold more: a bath or a teacup?
Answers:
  1. 1000 ml
  2. The 1 litre bottle holds more
  3. 550 ml
  4. 4 cups
  5. A bath holds more

FAQ

What is capacity in maths?

Capacity is how much a container can hold, usually measured in litres or millilitres.

How do you measure capacity?

You can measure capacity using a measuring jug or container with markings. Pour the liquid into the measuring container and read the level.

What are some real-life examples of capacity?

Examples include water bottles, bathtubs, cooking pots, glasses, and juice boxes. These all have different capacities.

How can I help my child learn about capacity?

Use containers at home to measure and compare liquids. Ask questions like “Which holds more?” and let your child guess before measuring.

What are some common units for capacity?

Common units are millilitres (ml), litres (l), cups, pints, and gallons. In the UK, we mostly use millilitres and litres.