Trade Calc Toolkit
Electrical, HVAC, concrete, framing, masonry, and solar calculators for contractors and estimators — NEC/ASHRAE-based formulas, no external API.
How to pay
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$9.99/month
Predictable monthly cost with included usage. Best for steady, high-volume traffic.
- Unlimited tools within plan limits
- One API key, billed once a month
- Cancel any time
A field-ready calculator toolkit for contractors, estimators, and ops agents — 15 tools spanning six trades, all computed locally from public engineering standards (NEC, ASHRAE, ACI). Electrical: voltage drop, wire sizing, conduit fill, service load calculation, box fill. HVAC: duct sizing (round and rectangular, ACCA/ASHRAE equal-friction method). Concrete: volume and bag counts, rebar layout with lap-splice estimating. Carpentry: stair stringers, rafter length, framing stud counts, board feet. Masonry: CMU block and mortar estimating. Solar: array sizing and NEC 690.7 cold-temperature string voltage checks. Every tool returns a clear disclaimer — this is a planning/estimating aid, not a substitute for code review by a licensed professional.