Calculators for the work, not the homework.

Precise tools for people who cut cloth, stack lumber, order a yard of gravel, pour a slab, load a bar, build an arrow, mix a dough, or price a listing.

Popular

Concrete Yards and bags for a slab. Gravel Tons and yards for a pad. Tire Size Two molded sizes, side by side. Stair Stringer Risers and the stringer length. Voltage Drop Volts lost along a run. BTU A room cooling estimate. Mulch Bags and yards for a bed. Ohm's Law Volts, amps, ohms, and watts.

Build

Construction Stairs, roof pitch, roofing, and truss lengths. 4 calculators Concrete Yards, bags, rebar, and block. 5 calculators Landscape Gravel, mulch, soil, and stone. 4 calculators Finish Tile, drywall, and fence takeoffs. 3 calculators Woodworking & building Board feet, battens, rafters, and stringers. 4 calculators Plumbing Tanks, pipe volume, and friction loss. 3 calculators Electrical Wire size, voltage drop, and box fill. 6 calculators HVAC BTU, tonnage, ducts, and mini-splits. 4 calculators Solar Array size, battery runtime, and kWh. 3 calculators

Make

Fiber & maker crafts Quilts, yarn, resin, and candles. 12 calculators Metal Weight, speeds and feeds, and print cost. 3 calculators Electronics Ohm’s law, filters, antennas, and PCB traces. 15 calculators Kitchen Dough, gravity, and alcohol by volume. 3 calculators

Outdoors and sport

Outdoors, aviation & archery Arrows, ballistics, and ski size. 7 calculators Strength & sport RPE, DOTS, and bowling. 3 calculators Automotive Tires, gears, offset, and displacement. 5 calculators Pool Gallons, salt, and aquariums. 3 calculators

Business

Sellers Etsy, PayPal, Stripe, and Whatnot fees. 4 calculators

Classic tools

Classic tools Scientific, mortgage, BMI, and bases. 4 calculators

A note on the old site

calculator.pro was a general calculator from 2013 to 2021. The links people made then — scientific, mortgage, BMI, decimal/binary/hex — now land on working versions of those tools. Ovulation and pregnancy URLs come back to this page. This site does not publish medical calculators.

Classic tools are listed quietly on purpose. The work is in the sections above.