Who it’s for
Carpenters, builders and DIYers on site, tape in hand.
What it does
- Add, subtract, multiply and divide feet, inches and fractions exactly, like 5' 7-3/8".
- Multiply lengths for square feet, cubic feet and cubic yards.
- Every length also shows in total inches, decimal feet and metric (cm, mm or m).
- Answers to the nearest 1/16", or any step from 1/2" to 1/64".
- The history keeps every answer: tap one to reuse it, or copy and share it.
- 11 tools, from stairs, roof pitch and rafters to concrete, board feet and miters.
- The stairs tool works out risers, treads, run and stringer, and shares the layout as a PDF.
- Works offline once your trial or purchase is active.
What it doesn't do
- No camera or laser measuring: you type the measurements in.
- No saved projects, jobs or estimates.
- Only the stairs tool makes a PDF, and only on US Letter (no A4).
- No hips or valleys between roofs of different pitches.
- No Android or web version.
Plans and prices
Free to download, with in-app purchases. Every feature, the calculator included, needs the free trial or a purchase.
- YearlyUS$9.99a year, 7-day free trial for eligible new subscribers
- LifetimeUS$19.99paid once, with Family Sharing
The app shows your local price before you buy.The Yearly plan renews at its price each year until you cancel, and you can cancel any time in your Apple Account settings. Lifetime is one payment; nothing renews. Prices are for the US App Store.
Screens
Your data
- No account or sign-up
- Your history and settings stay on your device, with no cloud sync
- The app sends usage analytics and crash reports to PostHog, with screen recordings: what you type into tool fields is hidden, but the calculator's display and results show
- The App Store privacy label lists Purchases, Location, User Content, Identifiers, Usage Data and Diagnostics as data linked to you; none is used to track you
Read the Construction Calculator privacy policy and the terms of use.
Free charts to print
All 7 charts and guides-
Fraction to decimal chart: inches, millimeters and feetEvery 64th of an inch as a decimal, in millimeters and in decimal feet. -
Roof pitch chart: degrees, slope and rafter lengthEvery pitch from 1/12 to 24/12: angle, slope and rafter length. -
Stair rise and run code: 7-3/4" risers, 10" treadsRisers, treads and run for stairs from 2' to 10', at code limits and the 7-11 rule. -
How to calculate board feetBoard feet for 1x4 to 6x6 lumber from 8' to 16' long, plus hardwood in quarters. -
How many bags of concrete in a yard?Bags of 80, 60 or 40 lb concrete per yard, and for slabs from 8' × 8' to 24' × 24'. -
How to calculate square footage from inches and fractionsSquare feet from feet, inches and fractions, for rooms, tile, sheets and doors. -
Crown molding angles chart: miter and bevel settingsMiter and bevel settings for 52/38 and 45/45 crown, for corners from 60° to 150°.
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Get Construction Calculator on the App Store
Feet, inches and fractions, done exactly. Stairs, roof pitch, rafters and concrete. No ads and no sign-up.
On a computer? Scan with your iPhone camera to open Construction Calculator on the App Store.Last updated .