19 calculators · all free
Free construction calculators
Concrete, framing, roofing, stairs, finish work and layout. Each page gives the formula and a worked example; each tool works it out with your own numbers, in feet and inches or metric.
Layout and measuring
Square footage calculator
Area, perimeter and the square-up diagonal of any room, slab or panel, in feet and inches.
Cubic yard calculator
Volume in cubic feet and cubic yards, plus floor and wall area, from three tape measurements.
Right triangle calculator
Any two of rise, run, diagonal and pitch give the rest: sides, angle, grade and area.
Circle area calculator
Area and circumference from a radius or a diameter, in the units you measure.
Framing and roofing
Roof pitch calculator
Pitch as x/12, degrees and percent, with the common rafter length for your run.
Roofing calculator
Roof area from the footprint and pitch, in squares, shingle bundles and sheathing sheets, with waste.
Stud calculator
How many studs a wall takes at 16 or 24 inches on center, with your waste allowance.
Stair calculator
Equal risers and treads, the stringer length and the stairwell opening from one total rise.
Deck calculator
Deck boards, joists and screws for your deck size, with every butt joint on a joist.
Concrete and masonry
Concrete calculator
Cubic yards to order for a slab or footing, with waste and weight, from feet and inches.
Concrete block calculator
How many blocks a wall takes, from its length and height, its area or one course.
Concrete bag calculator
Bags of concrete mix, or ready-mix, for round post holes, piers and sonotubes.
Finish and trim
Board foot calculator
Board feet per piece, for the whole list and to order, from nominal or actual sizes.
Crown molding calculator
Miter and bevel saw settings for any wall corner and spring angle.
Baluster spacing calculator
How many balusters fit between two posts and the exact even gap between them.
Drywall calculator
Sheets of each size for your walls and ceiling, less openings, with waste.
Paint, floors and tile
Paint calculator
Gallons or cans for walls and ceiling, with coats, primer and doors and windows taken out.
Tile calculator
Tiles and boxes for a floor, wall or backsplash, with the grout joint and waste.
Flooring calculator
Cartons of laminate, vinyl plank or hardwood, or rolls of carpet and sheet vinyl, with waste.
Need plain tape-measure math?
The calculator adds, subtracts, multiplies and divides feet, inches and fractions, with a tape of every result.