Construction Calculator: Feet

Construction Calculator adds, subtracts, multiplies and divides feet, inches and fractions. 12′ 3 5/16″ plus 7′ 8 7/16″ is 19′ 11 3/4″, and you enter it in that order with the Feet, Inch and fraction keys.

The calculator costs nothing, works offline and needs no account. Pro is a one time $6.99 purchase for nine tools, saved jobs and PDF sharing. There's no subscription.

The calculator
• The math keeps exact fractions between steps, so a long chain doesn't pick up rounding errors
• Round to 1/2″, 1/4″, 1/8″, 1/16″, 1/32″ or 1/64″. Rounded answers are marked, with the exact value underneath
• Results in feet and inches, inches, mm, cm or m. The Conv sheet converts any answer, yards included
• Square feet and cubic feet too: 10 feet times 12 feet gives 120 ft²
• Backspace to fix one key, and undo after you hit C
• The tape keeps every answer, newest first, even after you close the app. Tap a line to use it again
• Dark theme, plus Outdoor light, a bright theme for working in the sun

Pro tools
• Stairs: enter total rise, tread depth and max riser height to get riser count, riser height, tread count, total run, stringer length and stair angle. Add one landing, tread thickness to adjust the bottom riser, or a headroom check
• Rafter and roof pitch: rise, rafter length including overhang, slope factor, plumb cut and seat cut angles
• Right triangle: diagonal, angles and area. Check a corner for square with the diagonal you measured
• Concrete: slab, footing or column volume in cubic feet and cubic yards, 40, 60 or 80 lb bags, waste and a ready mix order quantity
• Block and brick: 8x16 block or modular brick for a wall, minus openings, plus waste
• Drywall: 4x8, 4x10 or 4x12 sheets for walls, with or without the ceiling, and an estimated screw count
• Paint: wall and ceiling area, coats and gallons to buy
• Flooring and tile: area with waste, tile count and boxes
• Board feet: lumber volume and cost for a stack

Each tool shows what you entered apart from what it calculated, with a short note on how it's worked out. You can try every tool with sample values before you buy.

Jobs
Save tape lines and tool results to a job, like "Back deck". Saved numbers stay exactly as you saved them. Share a job as a PDF through your phone's share menu, and export all your jobs to a JSON backup file you keep, then import it on a new phone.

Pay once
Pro is $6.99 once, through Google Play. No subscription and no account needed, and you can restore it on a new phone with the same Google account.

About ads
One small banner shows at the bottom of the Tools list, and nowhere else. No ads on the calculator, in tools, on results or in jobs. Pro removes the banner.

Stair code notes use common US values. Check your local building code, and measure twice before you cut. The app doesn't replace an inspection.