Formula
Each unit is converted through meters, using exact international definitions:
Result = value × meters in the source unit / meters in the target unit
An inch is 0.0254 meters and a foot is 0.3048 meters, so 1 foot is 12 inches.
Assumptions
- The international inch, foot, yard, and mile are used.
- No rounding is applied until the result is displayed.
- The value cannot be negative.
Worked example
1 foot converts to 12 inches. 1 kilometer converts to 1,000 meters.
Input definitions
- From
- The unit of the number you entered.
- To
- The unit you want the result in.
Limitations
This converts length only. It does not convert area, volume, or historical survey measures that differ slightly from the international foot.
Questions
Why is a foot exactly 12 inches?
Both units are defined from the meter: a foot is 0.3048 meters and an inch is 0.0254 meters.
Can I convert a unit to itself?
Yes. The result equals the number you entered.