Use the Metric to Imperial Conversions Explained
Metric to imperial conversion means changing a measurement from a metric unit, such as metres, kilograms or litres, into an imperial unit, such as feet, pounds or pints. Most everyday conversions use a fixed conversion factor.
To convert from one unit to another, multiply by the correct conversion factor. To go back the other way, divide by the same factor.
Want the answer without the manual maths?
Use the all-in-one unit converter for length, weight, temperature, volume and speed conversions.
How metric to imperial conversion works
A conversion factor is a number that links two units. For example, one inch is exactly 2.54 centimetres. That means centimetres can be converted to inches by dividing by 2.54, and inches can be converted to centimetres by multiplying by 2.54.
Converted value = original value × conversion factor
Reverse conversion = converted value ÷ conversion factorThe important part is using the right direction. If the result looks far too big or far too small, you may have multiplied when you needed to divide.
Length: centimetres, inches, metres, feet, miles and kilometres
Length conversions are common for height, furniture, screens, DIY, property, travel and road distances. In the UK, you will often see a mixture of metric and imperial units depending on context.
| Conversion | Formula | Example |
|---|---|---|
| cm to inches | inches = cm ÷ 2.54 | 180cm ≈ 70.87in |
| inches to cm | cm = inches × 2.54 | 10in = 25.4cm |
| metres to feet | feet = metres × 3.28084 | 2m ≈ 6.56ft |
| miles to kilometres | km = miles × 1.609344 | 10 miles ≈ 16.09km |
| kilometres to miles | miles = km ÷ 1.609344 | 5km ≈ 3.11 miles |
For a focused tool, use the length converter.
Weight: kilograms, pounds and stone
Weight conversions are common for body weight, food packaging, luggage, parcels, gym weights and product specifications. In the UK, body weight is often discussed in stone and pounds, while retail and official weights usually use metric units.
| Conversion | Formula | Example |
|---|---|---|
| kg to pounds | lb = kg × 2.2046226218 | 70kg ≈ 154.32lb |
| pounds to kg | kg = lb ÷ 2.2046226218 | 150lb ≈ 68.04kg |
| pounds to stone | stone = lb ÷ 14 | 154lb = 11 stone |
| stone to pounds | lb = stone × 14 | 12 stone = 168lb |
For body weight, the neatest UK result is often shown as stone and remaining pounds, such as 11 st 2 lb rather than 11.14 stone.
Volume: litres, millilitres, pints and gallons
Volume conversions are useful for drinks, fuel, recipes, containers, liquids and capacity. Be careful with pints and gallons because UK and US versions are different. Calculatorz pages should label these clearly rather than simply saying “pint” or “gallon”.
| Conversion | Formula | Example |
|---|---|---|
| litres to millilitres | ml = litres × 1,000 | 2L = 2,000ml |
| litres to UK pints | UK pints = litres × 1.759754 | 1L ≈ 1.76 UK pints |
| UK pints to litres | litres = UK pints × 0.568261 | 4 UK pints ≈ 2.27L |
| UK gallons to litres | litres = UK gallons × 4.54609 | 1 UK gallon ≈ 4.55L |
Temperature: Celsius and Fahrenheit
Temperature conversion is slightly different from most unit conversions because it uses a formula with both multiplication and addition. You cannot simply multiply Celsius by a fixed number to get Fahrenheit.
Fahrenheit = (Celsius × 9/5) + 32
Celsius = (Fahrenheit - 32) × 5/9| Celsius | Fahrenheit | Common meaning |
|---|---|---|
| 0°C | 32°F | Water freezes |
| 20°C | 68°F | Mild room temperature |
| 37°C | 98.6°F | Approximate human body temperature |
| 100°C | 212°F | Water boils at sea level |
For oven gas marks and fan oven temperatures, use the oven temperature converter in the Food & Cooking silo.
Speed: mph and km/h
Speed conversions are common for driving, travel, cycling, running, weather and boats. UK road speeds are usually shown in miles per hour, while many international contexts use kilometres per hour.
km/h = mph × 1.609344
mph = km/h ÷ 1.609344
m/s = km/h ÷ 3.6
km/h = m/s × 3.6For example, 70 mph is about 112.65 km/h, and 100 km/h is about 62.14 mph.
How much should you round converted measurements?
The right level of rounding depends on the job. Everyday conversions do not always need lots of decimal places, but DIY, engineering, health and scientific measurements may need more precision.
Common metric to imperial conversion mistakes
- Multiplying when the conversion should be divided.
- Confusing UK pints and gallons with US pints and gallons.
- Rounding too early in a multi-step calculation.
- Using volume conversions when the job needs weight.
- Showing decimal stone when stone and pounds would be clearer.
- Assuming all conversions work with one simple multiplier, including temperature.
FAQs
How do you convert metric to imperial?
Use the correct conversion factor for the units you are converting. For example, inches = centimetres ÷ 2.54, pounds = kilograms × 2.2046226218, and miles = kilometres ÷ 1.609344.
What is the easiest metric to imperial conversion?
The easiest method is to use a calculator, but the maths is usually multiplication or division by a fixed conversion factor. Temperature is different because Celsius and Fahrenheit use a formula with addition as well as multiplication.
How many pounds are in a kilogram?
There are about 2.2046 pounds in one kilogram. For everyday use, many people round this to 2.2 pounds per kilogram.
How many centimetres are in an inch?
One inch is exactly 2.54 centimetres. To convert inches to centimetres, multiply by 2.54. To convert centimetres to inches, divide by 2.54.
Why do UK users still need imperial conversions?
The UK uses metric units in many official and retail contexts, but imperial units are still common in everyday life, especially for road distances, height, body weight, pints and property measurements.
Sources and notes
This guide uses stable conversion factors and practical UK examples. For legal measurement context in the UK, refer to GOV.UK weights and measures guidance. For metric unit definitions, refer to the International System of Units.