Professional Trade Calculators for Real World Projects
Accurate, easy to use calculators, NEC-based solutions and practical guides for construction, electrical, plumbing, HVAC and more.
NEC & Industry Standards
Code-based calculations
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Formulas & references
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Contractors, builders, electricians
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Explore Trade Calculators
Instant calculations, reference tables and worked examples for every trade.
Construction & Framing
Concrete, roofing, stairs, deck, wall framing and more.
Electrical & Conduit
Wire size, voltage drop, conduit fill, box fill, load calculations.
Plumbing & Piping
DFU, WSFU, pipe sizing, water supply and drainage.
HVAC & Airflow
BTU, CFM, duct sizing, heating and cooling.
Materials & Takeoff
Gravel, aggregate, drywall, material quantities.
Featured Calculators
Most popular tools used by contractors, builders and trades professionals.
NEC Worked Solutions
Real-world electrical problems with step-by-step solutions and interactive calculators.
Subpanel Feeder Sizing
Calculate feeder size for a 60A subpanel with 75 ft run.
Conduit Fill Example
Calculate allowable fill for three 4 AWG THHN wires in EMT.
Motor Full Load Current
Calculate FLC and OCPD for a 5 HP, 3-phase motor.
Residential Load Calculation
Complete dwelling unit load calculation example.