Feet & Inches Calculator
Add or subtract two construction and DIY measurements without manually carrying inches into feet. Enter whole or decimal feet and inches as a number, fraction, or mixed fraction.
Enter two measurements
Result
Enter two measurements and calculate to see the normalized result and metric equivalents.
Formula and example
Convert each measurement to total inches: feet × 12 + inches. Add or subtract the totals, then divide by 12 to normalize the result. One inch equals 2.54 centimeters exactly.
Example: 5 ft 11½ in + ½ in = 72 in = 6 ft. A subtraction can be negative; for example, 2 ft − 2 ft ⅜ in = −⅜ in.
How to use this calculator
- Enter feet, inches, or both for each measurement. Leave a unit field blank when it is zero.
- Use the operation menu to add, or subtract the second measurement from the first.
- Select Calculate to display normalized feet and inches, decimal inches, centimeters, and meters.
- Use Reset to clear the inputs, or copy the formatted result.
Frequently asked questions
Which inch fractions can I enter?
Enter common fractions such as 1/2, 3/8, and 5/16, as well as mixed values such as 5 3/8. A decimal value is also accepted.
What happens if subtraction produces a negative result?
The calculator keeps the negative sign on the measurement and formats the magnitude normally, such as −3/8 in.
Are fractional inches rounded during calculation?
Fractions are represented exactly during addition and subtraction. Decimal and metric equivalents are rounded only for display.