Feet and Inches Calculator: Add, Subtract
This feet and inches calculator does tape-measure math. Type lengths the way you write them on a job site, such as 5' 7 1/2", 12 ft 3 in, 67.5 in or 8', then add, subtract, multiply or divide. Multiply or divide by a plain number to scale a cut or split a board into equal pieces, or divide one length by another to see how many pieces fit. Answers are shown in feet and inches rounded to the nearest 1/16, 1/8 or 1/4 inch, plus total inches, decimal feet, meters and centimeters. It is built for carpenters, DIY projects, sewing and room layouts.
Feet and Inches Calculator
Do math with lengths like 5' 7 1/2" and get answers in feet, inches and fractions.
How to use the Feet and Inches Calculator
- Type the first length, like 5' 7 1/2".
- Pick add, subtract, multiply or divide.
- Type the second length, or a plain number to multiply or divide by.
- Choose the rounding and read the answer.
Feet and inches math
Convert everything to inches (feet × 12 + inches), do the math, then convert back: feet = floor(total ÷ 12), inches = the remainder, rounded to the chosen fraction.
Features
- Accepts 5' 7 1/2", 5 ft 7 in, 67.5 in
- Add and subtract lengths
- Multiply or divide by a number
- Pieces per length
- Rounds to 1/16, 1/8 or 1/4 inch
- Decimal feet, meters and cm
Frequently asked questions
How do I add feet and inches?
Add the inches, carry every 12 inches to feet, then add the feet. 5' 8" + 3' 7" = 8' 15" = 9' 3".
How do I type a fraction of an inch?
Put a space before the fraction: 7 1/2". You can also type decimals such as 7.5 in.
What does a number with no unit mean?
When adding or subtracting, a plain number is read as feet. When multiplying or dividing, a plain second number is a multiplier or divisor.
How do I convert feet and inches to decimal feet?
Divide the inches by 12 and add the feet. 5' 6" = 5 + 6/12 = 5.5 ft.
How do I split a board into equal pieces?
Divide the length by the number of pieces. 8' ÷ 3 = 2' 8". Remember to allow for the saw kerf.