Metric and imperial
The metric units step by tens: 10 mm is 1 cm, 100 cm is 1 m, 1,000 m is 1 km. The imperial ones do not: 12 inches make a foot, 3 feet a yard and 1,760 yards a mile. Since 1959 every imperial length has been defined in metres, so the bridge between the two is exact: 1 inch is 2.54 cm, 1 foot is 30.48 cm and 1 mile is 1,609.344 m.
Heights in feet and inches
The converter takes one unit at a time, so for a height like 5 ft 9 in, turn it into inches first: 5 × 12 + 9 = 69 inches, which is 175.26 cm. Going the other way, 180 cm is 70.87 inches, which is 5 ft 10.87 in.
Nautical miles
A nautical mile is exactly 1,852 m, about 1.15 ordinary miles. Sea and air navigation use it because one nautical mile is close to one minute of latitude. Speeds in knots are nautical miles per hour; those are on the Speed Converter.
One pair at a time
The pairs people look up most have a page each, opened on that pair with a table of common values: cm to Inches, Inches to cm, Feet to Meters, Meters to Feet, Miles to km and km to Miles.
Questions
How many feet are in a metre?
3.28084, to five decimal places. A metre is 39.37 inches, a little over 3 feet 3 inches.
Can I type 5'9"?
No. Type one number in one unit: turn feet and inches into inches first (5 × 12 + 9 = 69) and type 69 with inches chosen.
Which mile is this?
The international mile, 1,609.344 m, used for road distances in the US and the UK. The US survey mile found in some old land records is about 3 mm longer and is not listed.