Units of measurement

Enter a value and convert instantly between metric units, imperial units, and metric-imperial bridges for length, mass, capacity and time.

Curriculum rangeYears 2-11

25\ \text{feet} = 762\ \text{centimetres (cm)}

Learning notes

Units of measurement essentials

Keep these rules beside you while you explore and practise.

1Metric units

All metric conversions are powers of 10 -- multiply or divide by 10, 100 or 1,000.

10\ \text{mm} = 1\ \text{cm}, \quad 100\ \text{cm} = 1\ \text{m}, \quad 1000\ \text{m} = 1\ \text{km}

2Imperial units

Imperial conversions don't follow a pattern -- these are worth memorising: $12\,\text{in}=1\,\text{ft}$ , $3\,\text{ft}=1\,\text{yd}$ , $1{,}760\,\text{yd}=1\,\text{mi}$ .

3Common metric-imperial equivalents

Handy estimates for quick mental maths (the calculator uses exact values):

5 miles ≈ 8 km
1 inch ≈ 2.5 cm
1 kg ≈ 2.2 pounds
1 gallon ≈ 4.5 litres

4Capacity and volume

$1\,\mathrm{cm}^3$ holds exactly $1\,\mathrm{ml}$ , so $1{,}000\,\mathrm{cm}^3=1\,\mathrm{litre}$ .

5Time

$60\,\text{s}=1\,\text{min}$ , $60\,\text{min}=1\,\text{h}$ , $24\,\text{h}=1\,\text{day}$ , $7\,\text{days}=1\,\text{week}$ . Months and years vary in length, so their conversions are averages.

💡Multiplying by a bigger unit's factor, then dividing by the target unit's factor, always gets you from one unit to any other -- that's exactly what the converter above is doing.