Construction calculators
18 free tools for layout, concrete, framing, roofing, decks, fences and finishes. Imperial and metric, with formulas and worked examples on every page.
Layout
3-4-5 Squaring Calculator
Find the exact diagonal for a square corner and check a measured one.
Right Triangle (Pythagorean) Calculator
Solve any right triangle from two sides: hypotenuse, angles, area.
Rectangle Diagonal Check Calculator
Compare two diagonals to prove a frame, slab or room is square.
Square Footage Calculator
Area of rooms and L-shapes, in ft² and m², with cost.
Concrete
Concrete Slab Calculator
Cubic yards, cubic metres and bag counts for slabs and pads.
Post Hole & Footing Concrete Calculator
Concrete for round post holes and pier footings.
Roofing
Roof Pitch Calculator
Pitch, angle, slope % and roof area from rise and run.
Rafter Length Calculator
Common rafter length, ridge height and plumb cut from span and pitch.
Framing
Stair Calculator
Riser count, riser height, treads, total run and stringer length.
Board Feet Calculator
Board feet, cubic volume and cost of lumber.
Decks & fences
Deck Board Calculator
Boards, linear feet, joists and screws for a rectangular deck.
Fence Calculator
Posts, rails, pickets and concrete for a straight-run fence.
Finishes
Tile Calculator
Tiles and boxes for floors, walls and backsplashes.
Flooring Calculator
Boxes of laminate, vinyl plank or hardwood plus underlayment.
Paint Calculator
Gallons or litres of paint and primer for a room.
Drywall Calculator
Sheets, tape, compound and screws for a room.
Landscape
Masonry
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