How to use it
- Type a number. Commas, decimals and scientific notation (such as 2.5e3) all work.
- Choose the unit you have and the unit you want. Use the swap button to reverse the direction.
- Read the result, check the factor underneath, and copy it with one click.
How the conversion works
Every length unit here is defined exactly in meters. The inch has been defined as exactly 2.54 centimeters since the 1959 international yard and pound agreement, and the other US customary units follow from it:
1 in = 2.54 cm (exact)
1 ft = 12 in = 30.48 cm = 0.3048 m (exact)
1 yd = 3 ft = 0.9144 m (exact)
1 mi = 5,280 ft = 1,609.344 m (exact)
result = value × (meters per source unit ÷ meters per target unit)
To stay exact, the calculator keeps each factor as an exact fraction and divides them before touching your number. Ordinary floating-point arithmetic would say one foot is 12.000000000000002 inches; this converter says 12.
Worked examples
180 cm in feet
180 ÷ 30.48
5.9055 ft
5 miles in kilometers
5 × 1.609344
8.04672 km
12 inches in centimeters
12 × 2.54
30.48 cm
100 meters in feet
100 ÷ 0.3048
328.084 ft
10 km in miles
10 ÷ 1.609344
6.2137 mi
1 yard in meters
1 × 0.9144
0.9144 m
Where this comes up
- Home and DIY: furniture listed in centimeters, rooms measured in feet.
- Running and travel: a 5K is 3.107 miles; road signs abroad are in kilometers.
- Screens and gadgets: diagonals in inches, product dimensions in millimeters.
- School and science: lab work in metric, everyday US measurements in feet and inches.
Accuracy and rounding
Results are calculated at full precision and rounded only for display. “Auto” shows up to 10 significant digits; you can choose a fixed number of decimal places instead. The badge next to the result says Exact when the digits shown are the complete answer and Rounded when more digits exist.
This converter uses the international foot. The older US survey foot (about 2 parts per million longer) was retired by NIST at the end of 2022 and is only relevant to some historical land surveys.
Questions
How many centimeters are in a foot?
Exactly 30.48 cm, because a foot is 12 inches and each inch is exactly 2.54 cm.
How many feet are in a mile?
Exactly 5,280 feet, which is 1,760 yards or 1,609.344 meters.
Is a meter longer than a yard?
Yes. A meter is about 1.0936 yards (3.2808 feet), roughly 9% longer than a yard.
Why does the ruler change its scale?
So your value always fills a readable part of the ruler. The scale changes only in fixed steps, and both scales always share the same physical scale.