Length is the unit people convert most often, because the metric and imperial systems are both alive and well: centimeters and inches for body measurements and screen sizes, meters and feet for heights and rooms, kilometers and miles for distances and road signs, millimeters for precision work, yards for fabric and sport. All of these units are tied together by exact definitions — since 1959 one inch is exactly 25.4 mm — so every conversion on this page is precise, not approximate.

Conversion factors at a glance

Unit	Equals
1 inch	2.54 cm = 25.4 mm
1 foot	12 inches = 30.48 cm = 0.3048 m
1 yard	3 feet = 0.9144 m
1 mile	1 760 yards = 5 280 feet = 1.609 km
1 meter	100 cm = 3.281 feet = 1.094 yards
1 kilometer	1 000 m = 0.621 miles

Which converter do I need?

Height. Centimeters to inches, then inches to feet for the "5 ft 10 in" form; or meters to feet directly. Screens, paper and small parts. Millimeters to inches and back. Rooms and furniture. Feet to meters and inches to cm. Travel and running. Miles to kilometers for road distances and race lengths. Fabric, golf and American football. Yards to meters.

Metric or imperial?

Only the United States uses imperial units for almost everything. The United Kingdom mixes both: road signs in miles, height often in feet and inches, but building materials and most shopping in metric. Canada, Australia, Ireland and India switched to metric decades ago but still hear inches and feet in everyday speech. Everywhere else, and in every scientific and engineering context, the meter and its multiples are standard.

Common questions

How tall is 180 cm in feet? 5 ft 11 in. How many centimetres is 6 feet? 182.9 cm. How long is a mile in km? 1.609 km; a 5K run is 3.1 miles and a marathon (42.195 km) is 26.2 miles. What is 1 metre in feet? 3.28 ft, about 3 ft 3 in. How many mm in an inch? Exactly 25.4.