Free Online Calculators
Quick answers to the calculations electricians do every day — voltage drop, conduit fill, ampacity, box fill, and motor sizing. All based on the current NEC.
Calculate voltage drop in volts and percentage for a single-phase or three-phase circuit. Helps you size conductors for long runs while staying under NEC-recommended drop limits.
Check whether your conductor combination fits within NEC fill limits for the chosen raceway. Supports same-size and mixed-size fills.
Look up conductor ampacity with adjustments for ambient temperature and conductor count. Coming soon.
Calculate required cubic-inch volume for a junction or device box based on conductor counts, devices, and clamps. Coming soon.
Size motor branch conductors, OCPDs, and overload protection for single- and three-phase motors. Coming soon.
These calculators are educational aids. Always verify against the current National Electrical Code and consult a licensed engineer for production designs.