Free tools · 21 calculators
Free Home Improvement Calculators
Measure once, buy once. Figure out lumber, stairs, gravel, paint, wire gauge and more before you head to the store. Every calculator shows its math.
- No sign-up
- Works on your phone at the job site
- Shows the formula, not just the answer
Woodworking & Carpentry
5 tools01Calculator
Board Foot CalculatorBoard feet, stack totals and cost for rough or dimensional lumber.Open tool02Calculator
Stair Stringer CalculatorRise, run, stringer length and a cut layout that meets code.Open tool03Calculator
Roof Pitch & Rafter CalculatorPitch, angle and rafter length from rise and run.Open tool04Chart + finder
Drill Bit Size ChartPilot holes, clearance holes and tap drill sizes in one lookup.Open tool05Optimizer
Cut List OptimizerLay out your parts on sheet goods and boards with less waste.Open toolOutdoor & Landscape
6 tools06Calculator
Gravel CalculatorCubic yards and tons of gravel for driveways, paths and bases.Open tool07Calculator
Mulch CalculatorCubic yards or bags of mulch for any bed shape.Open tool08Calculator
Topsoil CalculatorHow much soil to fill beds or level a lawn.Open tool09Calculator
Sod CalculatorSquare feet, pallets and rolls of sod with waste.Open tool10Calculator
Cubic Yard CalculatorConvert any length, width and depth to cubic yards.Open tool11Calculator
Concrete CalculatorSlabs, footings and posts in yards or 60 and 80 lb bags.Open toolInterior & Finishing
4 tools12Calculator
Paint CalculatorGallons for walls and ceilings, minus doors and windows.Open tool13Calculator
Drywall CalculatorSheets, screws, mud and tape for any room.Open tool14Calculator
Wallpaper CalculatorRolls needed, with pattern repeat and waste.Open tool15Calculator
Square Footage CalculatorArea of rooms and odd shapes, added up.Open toolElectrical & Lighting
3 tools16Layout planner
Recessed Lighting CalculatorHow many can lights, what spacing, and a layout you can see.Open tool17Calculator
Extension Cord Gauge CalculatorThe right cord gauge for your tool, amps and run length.Open tool18Calculator
Generator Wattage CalculatorAdd up running and starting watts to size a generator.Open toolHeating, Cooling & Water
3 toolsCalculators give estimates. Check local building codes and manufacturer specs before you build or buy. Looking for gear instead? Browse our tool reviews and buying guides.