Contractor Calc Pro Every calculation a contractor needs.
20 tools, code-compliant, works offline. From stair risers to septic systems — get the right answer the first time.
10 calculators for the job site.
Everything from code-compliant stair layouts to rebar schedules. No internet required.
- Stair Calculator — risers, treads, stringer length & IRC check
- Drywall Estimator — sheets, screws, tape, mud & corner bead
- Gutter & Downspout — SMACNA sizing by roof area & rainfall
- Rebar Calculator — bar count, weight & cut list
- Deck Materials — full BOM: boards, joists, posts & hardware
- Septic System — tank size & drain field by bedrooms & soil
IRC, NFPA 211, SMACNA built in.
Get code-compliant answers, not just numbers. Every result is checked against the relevant building code so you can build with confidence.
- IRC stair rise/run limits flagged automatically
- NFPA 211 flue sizing for every chimney configuration
- SMACNA gutter sizing by rainfall intensity region
- IRC insulation R-value minimums by climate zone
Full material lists with cost estimates.
Every calculator outputs a complete bill of materials — quantities and estimated costs included. Take it straight to the lumber yard.
- Deck BOM: decking, joists, posts, footings, hardware & railing
- Drywall BOM: sheets, screws, joint tape, compound & corner bead
- Rebar: bar count, lap splices, chairs & total weight
- Save any result to Recent Calculations for quick reference
Built for the tools you actually use.
Every calculator is designed for real job-site conditions — not textbook examples.
Stair Calculator
Enter total rise and run, get risers, treads, stringer length, cut angle, and an IRC compliance check.
Deck Materials
Full deck BOM from a single footprint input — boards, joists, posts, footings, hardware, and railing included.
Septic System
Size a septic tank and drain field from bedrooms and soil perc rate. Code references included.
Roof Area
Footprint plus pitch gives you exact squares for shingles, underlayment, and ridge cap. Pro pack tool.
Unlock 5 more tools with Pro.
The Carpentry Pack adds framing, concrete, roof pitch, roof area, and board feet calculators — the tools carpenters, framers, and roofers reach for every day.
One-time purchase. No subscription.
Ready for the job site?
Download free and start calculating. No account, no subscription, no internet required on the job.
Free download · Carpentry Pack available as one-time Pro upgrade