Metric vs. imperial length units
Most of the world uses the metric system (millimetres, centimetres, metres, kilometres), built on powers of ten, which makes converting between units a matter of shifting a decimal point. The imperial/US customary system (inches, feet, yards, miles) is still used for everyday measurements in the United States and, informally, in the UK — which is why conversions between the two systems come up so often in cooking, construction, travel, and shopping.
Common conversions people search for
- Centimetres to inches — clothing sizes, screen sizes, height
- Feet and inches to metres — room dimensions, furniture
- Miles to kilometres — driving distances, race lengths
- Millimetres to inches — engineering and hardware specs
Frequently asked questions
Why do the US and UK use different units day to day?
The UK officially adopted the metric system for most purposes but still uses imperial units informally for things like road distances and body height, while the US never fully switched from the imperial system.
How precise are these conversions?
They use standard, exact conversion factors (for example, 1 inch = 2.54 cm exactly), so results are as precise as the number of decimal places shown.