Feet & Inches Calculator (Add, Subtract, Multiply, Divide Fractions)
Construction calculator for feet-inch-fraction arithmetic and dividing a length into equal spaces · free, no signup
See Feet & Inches Calculator (Add, Subtract, Multiply, Divide Fractions) in action
Free Feet & Inches Construction Calculator
Working with a tape measure means working with feet, inches and fractions, and ordinary calculators make that painful. This calculator lets you type measurements exactly as you read them — 5′-6 1/2″, 5′ 6-1/2″, 5ft 6in, 66.5″, 5.5′ or 3/4″ — and combine them with + , − , × and ÷: add a list of lengths, subtract a cut, multiply by a count, divide by a number, or divide one length by another to get a ratio. The result is shown in feet-and-inches rounded to the nearest 1/2, 1/4, 1/8, 1/16, 1/32 or 1/64 inch, with the rounding error, plus decimal inches, decimal feet, millimetres and metres. Multiplying two lengths gives an area in square feet.
A second tab divides a total length into equal spaces — for example a 10′-3 1/2″ span into seven equal spaces for balusters, studs or deck boards — and lists every mark, or computes the equal gap between posts or boards of a known width, which is the classic fence and baluster layout problem. Everything runs in your browser.
Key features
Tape-measure notation
Type 5′-6 1/2″, 66.5″ or 5ft 6in just like on a plan.
All four operations
Add, subtract, multiply, divide, ratios and areas.
Rounding to any fraction
Nearest 1/2″ to 1/64″ with the error shown.
Equal-space layout
Divide a span or find the gap between posts and boards.
How to use it
- Type a calculation or choose an example chip.
- Pick the fraction precision.
- Read the result in feet-inches, decimal and metric.
- Use the second tab to divide a length into equal spaces.
Worked example
Example
5′-6 1/2″ + 3′-2 3/4″ = 8′-9 1/4″ (105.25 in = 2.673 m); 12′-0″ ÷ 7 = 1′-8 9/16″ (to the nearest 1/16″); 10′-3 1/2″ − 2′-8″ = 7′-7 1/2″.
Who uses this tool
Carpenters and builders
Cut lists, layouts and stair calculations.
DIYers
Deck, fence and shelf measurements.
Designers
Convert plan dimensions to decimals.
Tips for the best results
- Put spaces around a minus sign so it is not read as part of a measurement.
- Choose 1/16″ for framing and 1/32″ for finish work.
- Check the rounding error on long runs.
- Use the equal-space tab for baluster and stud spacing.
Common mistakes to avoid
- Typing 5-6 1/2 without a foot mark when you mean 5 feet 6 1/2 inches.
- Forgetting to round a cut to the saw's accuracy.
- Adding a length to a plain number.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
Which formats can I type?
Feet and inches with fractions, decimal inches or feet, and ft/in words.
Can it divide into equal spaces?
Yes — on the second tab.
Does it handle metric?
It shows mm and m for every result.
Is it free?
Yes.