How the conversion works
Every unit on this page is defined in terms of the metre, so converting between any pair of them is nothing more than multiplying by exact factors. Since 1959 the inch has been defined as exactly 2.54 cm, and the rest of the imperial ladder follows from it: 12 inches to the foot, 3 feet to the yard, 1,760 yards to the mile.
The tool converts your value into metres first, then back out into every other unit, and only rounds at the moment of display (to six significant figures). That means you can chain conversions without errors creeping in: 1 mile really is 1,609.344 m, 63,360 inches and 5,280 feet all at once.
Worked examples
Quick reference
- 1 mm ≈ 0.039 in, and 1 in = 25.4 mm
- 1 cm ≈ 0.394 in, and 1 in = 2.54 cm
- 1 m ≈ 3.281 ft, and 1 ft = 0.3048 m
- 1 m ≈ 1.094 yd, and 1 yd = 0.9144 m
- 1 km ≈ 0.621 mi, and 1 mi = 1.609344 km
- 1 ft = 30.48 cm, 1 yd = 91.44 cm
Metric and imperial, side by side
Britain never quite finished going metric, so both systems are still in daily use, often in the same sentence. Road signs and speed limits are in miles, athletics tracks and Ordnance Survey maps are metric, timber and tiles are sold in millimetres, and TVs are measured diagonally in inches. Builders switch between a metric tape measure and an imperial spec sheet all day long, which is exactly the kind of back-and-forth this converter is for.
Two lookalike units are deliberately not on this page. The nautical mile (1,852 m, about 15% longer than the road mile) belongs to sea and air navigation, so a distance quoted in "miles" by a sailor is not the one on your car's odometer. And horses are still measured in hands, at 4 inches to the hand, so a 16 hh horse stands 64 inches (about 163 cm) at the withers. If you meet either of those, convert through inches or metres and the numbers above still do the work.
A few habits worth keeping: for rough mental maths, a metre is "a yard and a bit" (about 10% longer), a kilometre is about five eighths of a mile, and 30 cm is close enough to a foot for most DIY. When precision actually matters, use the exact factors above rather than the folk versions. If it is specifically height you are converting, our cm to feet converter gives the answer in feet and inches the way people actually say it, and for road distances the miles to km converter has running and driving references built in.
Frequently asked questions
How many centimetres are in an inch?
Exactly 2.54 cm. The inch has been defined as exactly 2.54 cm since 1959, so every metric-imperial length conversion on this page is exact rather than approximate. A foot is 30.48 cm and a yard is 91.44 cm.
How do I convert metres to feet?
Divide the metres by 0.3048, or multiply by about 3.281. For example 100 m is 328.08 ft. Going the other way, multiply feet by 0.3048 to get metres.
How many kilometres are in a mile?
One mile is exactly 1.609344 km. So 5 miles is 8.05 km, and 5 km is about 3.11 miles. To convert km to miles, divide by 1.609344 or multiply by roughly 0.6214.
What is the difference between a yard and a metre?
They are close but not equal. A yard is exactly 0.9144 m, so a metre is about 1.094 yards, roughly 9.4 cm longer than a yard. Over 100 metres the difference adds up to more than 9 yards' worth of centimetres, which is why athletics switched to metric distances.
How accurate are the results?
The tool converts through metres using the exact legal definitions (1 in = 2.54 cm, 1 mi = 1.609344 km) and only rounds for display, to six significant figures. That is more precision than any tape measure can use.