We’re updating Ivy Maths.We apologise for any bugs while we make improvements. Thanks for your patience.

Reference

Key Measures

Learn the units, relationships and conventions used to measure length, mass, capacity, time, money and more.

From

To

1 kilometres = 1000 metres

The Rules

0 of 6 ticked

The Units

44 units

Length

Metric length steps up and down in thousands, hundreds and tens.

1 kilometre	= 1000 metres
1 metre	= 100 centimetres
1 metre	= 1000 millimetres
1 centimetre	= 10 millimetres

Mass

Weight in the metric system works in thousands.

1 tonne	= 1000 kilograms
1 kilogram	= 1000 grams
1 gram	= 1000 milligrams

Capacity

Liquid measure, and the litre that links to volume.

1 litre	= 1000 millilitres
1 litre	= 1000 cubic centimetres
1 centilitre	= 10 millilitres

Time

The one system that does not work in tens.

1 minute	= 60 seconds
1 hour	= 60 minutes
1 day	= 24 hours
1 week	= 7 days
1 year	= 365 days
1 leap year	= every 4 years

Money

Pounds and pence, and the way amounts are written.

£1	= 100 pence
50p	= £0.50
£2.05	= two pounds and five pence

Area

Area units square the length step, so the factors square too.

1 cm²	= 100 mm²
1 m²	= 10 000 cm²
1 hectare	= 10 000 m²
1 km²	= 100 hectares

Volume

Volume cubes the length step, so the factors cube too.

1 cm³	= 1000 mm³
1 m³	= 1 000 000 cm³
1 m³	= 1000 litres

Metric and Imperial

These are approximate. Use them for checking an answer is sensible, not for exact work.

1 inch	≈ 2.54 cm
1 foot	≈ 30 cm
1 mile	≈ 1.6 km
1 kilogram	≈ 2.2 pounds
1 stone	≈ 6.35 kg
1 litre	≈ 1.75 pints
1 gallon	≈ 4.5 litres

Temperature

Two scales, and the rule for turning one into the other.

Water freezes	= 0 °C, 32 °F
Water boils	= 100 °C, 212 °F
°C to °F	= × 9 ÷ 5 then + 32
°F to °C	= − 32 then × 5 ÷ 9