When to use it
Use this converter whenever you need to switch between metric and imperial lengths. It is handy for reading furniture sizes from another country, following a sewing or DIY plan, checking a running distance, working out a child’s height in the other system, or doing science homework with micrometers and kilometers.
How to use it
- Type a number in Value.
- Choose the unit you have under the value, such as Centimeters (cm).
- Choose the unit you want under Result, such as Inches (in).
- Read the answer in the result box and in the line below it.
- Use the swap button between the boxes to reverse the conversion, or Copy result to copy just the number.
The All conversions table below shows your value in every unit at once: millimeters, centimeters, meters, kilometers, inches, feet, yards, miles, nautical miles and micrometers.
Worked example
A desk is listed as 100 cm wide and you think in inches. Enter 100, choose centimeters and inches, and the result is 39.37007874 in, a little over 39⅓ inches. The table also shows 3.280839895 ft, so the desk is just under 3 feet 4 inches.
Going the other way, a 6-foot shelf is 6 × 30.48 = 182.88 cm. Swap the units and enter 6 with feet selected to check.
Useful numbers to remember
- 1 inch = 2.54 cm
- 1 foot = 30.48 cm
- 1 yard = 0.9144 m
- 1 mile = 1.609344 km
- 1 km = about 0.62 miles
Very small and very large lengths
Micrometers are used for things like the thickness of hair or paper: a sheet of office paper is about 100 µm. For long distances, kilometers and miles are easier to read than meters, so pick the unit that keeps the number simple.
Tips
- Round sensibly. Measuring tapes rarely go finer than a millimeter or a sixteenth of an inch, so there is no point keeping eight decimal places.
- Use the table for quick comparisons. It is faster than changing the to-unit several times.
- Check the unit before you cut. In DIY, a mix-up between inches and centimeters is an expensive mistake.
Common mistakes
- Treating 5.9 feet as 5 ft 9 in. 5.9 feet is 5 ft 10.8 in. Convert feet and inches separately.
- Confusing miles and nautical miles. Boat and flight distances are usually nautical.
- Mixing up thousands and decimals. The tool reads 1,250 as one thousand two hundred and fifty, and 12,5 as twelve and a half. If in doubt, type plain digits with a dot, such as 1250 or 12.5.