Builder's Math

Construction calculators for your next project

Work out how much concrete, gravel, topsoil, asphalt, tile, drywall, paint or shingles to buy before you go to the store. Free, no sign-up, and it works on your phone.

Concrete and landscaping

Concrete calculatorCubic yards and 40, 60 or 80 lb bags for slabs, footings and post holes.Cubic yard calculatorTurn length, width and depth into cubic yards for soil, sand, gravel or concrete.Gravel calculatorTons and cubic yards of gravel, crushed stone, sand or topsoil.Mulch calculatorCubic yards for bulk delivery or the number of bags for your beds.Topsoil calculatorCubic yards, bags and tons of topsoil for lawns, beds and raised gardens.Asphalt calculatorTons of hot-mix asphalt for a driveway or parking pad.

Floors and walls

Square footage calculatorSquare feet for rooms, floors and yards, including L-shapes, triangles and circles.Tile calculatorHow many tiles and boxes for a floor, wall or backsplash.Drywall calculatorSheets of 4×8, 4×10 or 4×12 for walls and ceilings, plus screws.Paint calculatorGallons and quarts for a room, after doors and windows.

Framing and roofing

Stair calculatorNumber of steps, riser height, total run and stringer length.Roofing calculatorRoof area, squares and shingle bundles from house size and pitch.Board foot calculatorBoard feet and cost of lumber from thickness, width and length.

Why use these calculators

  • Answers in what the store sells: bags, bundles, sheets, tons and gallons, not just volume.
  • Feet and inches the way you measured: type 12 ft 6 in straight in, or use yards, meters or centimeters.
  • Quick-answer tables for common sizes, and the math with a worked example on every page.
  • Save, share or print an estimate to take to the store or send to a contractor.
  • Works on the job site: add it to your phone’s home screen and pages you have opened keep working without signal.
  • Nothing to install or sign up for. The numbers you type stay in your browser.