11 free calculators · no sign-up · free to embed
Free Construction Calculators for Every Stage of the Job
From the first measurement to the last circuit: area, concrete, block, lumber, drywall, stairs, roofing, landscaping and electrical. Each calculator works in feet and inches, shows its formula and sources, and gives you a shopping list you can copy or print.
Which Calculator Do I Need?
Start with the area or volume of what you’re building, then the materials. Use square footage for floors and walls, concrete for slabs and footings, block for masonry walls, gravel for bases and drainage, board feet for lumber, stairs for steps, roof pitch for roofing, and conduit fill and voltage drop for wiring.
Framing, Carpentry and Roofing
Calculators by Project
A concrete patio
- Square footage calculator: Measure the area
- Gravel calculator: Order 4 in of gravel base
- Concrete calculator: Order concrete by the yard or bag
A block retaining or garden wall
- Concrete calculator: Pour the footing
- Concrete block and brick calculator: Count blocks and mortar
- Gravel calculator: Drainage gravel behind the wall
Finishing a basement
- Square footage calculator: Flooring area
- Drywall calculator: Drywall, mud and tape
- Stair and stringer calculator: Rebuild the stairs to code
- Voltage drop calculator: Size the new circuits
A deck with stairs
- Board foot calculator: Price the lumber
- Stair and stringer calculator: Lay out the stringers
- Concrete calculator: Footings and post holes
A new roof
- Roof pitch calculator: Pitch, area, squares and bundles
A detached garage or shop
- Concrete calculator: Slab
- Conduit fill calculator: Size the conduit
- Voltage drop calculator: Feeder wire size for the distance
How These Calculators Are Built
Every formula and number comes from a named source: the National Electrical Code tables, the International Residential Code, manufacturer data sheets (USG, Quikrete) and university extension guidance. Each calculator is tested against published values before it goes live, and the sources are listed on its page. Read our methodology.