Metric units conversion for 11+ maths
21 October 2026
Why metric units matter
Converting between metric units is a key skill for the 11+ maths exam. Children are often asked to change between millimetres, centimetres, metres, kilometres, millilitres, litres, grams and kilograms. Practising these conversions helps build confidence and speed.
Common metric units in 11+ maths
Typical questions might involve length (mm, cm, m, km), mass (g, kg) or capacity (ml, l). Knowing how these units relate makes it easier to tackle a wide range of problems.
Worked example
Convert 2500 millilitres to litres
Step 1: Know the relationship. 1 litre = 1000 millilitres.
Step 2: To change millilitres to litres, divide by 1000.
Step 3: 2500 ÷ 1000 = 2.5
The correct answer is 2.5 litres.
Key insight: Understanding the basic relationships between metric units (such as 1000 millilitres in a litre or 100 centimetres in a metre) allows children to convert quickly and accurately, which is essential for 11+ success.
Building confidence through practice
Encourage your child to practise converting metric units regularly. Working through examples together helps them develop a clear method and approach each question with confidence.
