Free calculators for common building jobs. Each one runs in your browser, and nothing you type is sent anywhere. Enter your measurements and get the numbers you need to buy materials or mark a cut.
- Stair stringer calculator: risers, treads, stringer length and a printable cut sheet, checked against the 2021 IRC or IBC.
- Paver calculator: the paver count with cut waste, base gravel and bedding sand in cubic yards and tons, and the edge restraint length.
- Roof pitch calculator: pitch from rise and run, an angle or a slope percent, rafter length from the run, and a printable pitch chart.
- Concrete slab calculator: cubic yards for one or more slabs, a waste allowance, and the count of 40, 60 or 80 lb bags.
Check local building code and the manufacturer’s instructions. Structural and roofing work may need a permit or a professional.