Feet and Inches Calculator
Add, subtract, multiply or divide lengths in feet, inches and fractions of an inch, just like on a tape measure.
How to use the Feet and Inches Calculator
- Enter the first length – feet.
- Enter the first length – inches – Fractions like 7 1/2 or 3/8 are allowed.
- Choose the operation.
- Enter the second length – feet.
- Enter the second length – inches.
- Enter the number.
- Choose the fraction precision.
- Press Calculate. The result updates automatically as you type, and you can switch the result unit at any time.
About the Feet and Inches Calculator
Builders, carpenters and DIYers work in feet, inches and fractions every day. Adding 5′ 7½″ and 3′ 9¾″ by hand means carrying inches into feet and adding fractions with different denominators. This calculator handles all of that, and also shows the answer in decimal feet and metric units.
Formula
Convert each length to inches, do the math, then convert back:
total inches = feet × 12 + inches
feet = ⌊total inches ÷ 12⌋, inches = remainder
The leftover decimal inches are rounded to the nearest fraction you choose (for example 1/16"), the same marks you see on a tape measure.
Example calculation
Using the default values:
- First length – feet = 5 ft
- First length – inches = 7 1/2 in
- Operation = Add (+)
- Second length – feet = 3 ft
- Second length – inches = 9 3/4 in
- Fraction precision = 1/16"
the calculator returns:
- Result (feet & inches): 9′ 5 1/4″
- Result length: 113.25 in
- Decimal feet: 9.4375 ft
Frequently asked questions
How many inches are in a foot?
There are 12 inches in one foot.
How do I convert decimal feet to feet and inches?
Keep the whole number as feet, then multiply the decimal part by 12 to get inches. For example 5.75 ft = 5 ft + 0.75 × 12 = 5 ft 9 in.
How do I add fractions of an inch?
Convert the fractions to a common denominator (such as sixteenths), add the numerators, and simplify. 3/8″ + 1/4″ = 6/16″ + 4/16″ = 10/16″ = 5/8″.
Last updated: · Category: Construction calculators