Electrical calculations
Choose a worksheet, enter your values, and print or save the result as a PDF. Each tool shows its steps and scope.
Residential Load Calculator
Enter household loads, review the service estimate, and print a single-page report.
Charger kW ampacity calculation
Three-phase AC input current, a 125% continuous-load allowance, and a preliminary standard OCPD rating.
Open calculation →02EV charging power
Estimate single-phase AC charging power from voltage and charging current.
Open calculation →03EV charging time & energy
Estimate energy and charging hours from battery size, target charge, and AC power.
Open calculation →04Commercial lighting load
General lighting load from floor area and an applicable occupancy unit value.
Open calculation →05Voltage drop estimate
Estimate voltage drop from conductor size, material, current, and one-way length.
Open calculation →06Conduit fill
Check equal-size conductor area against general raceway fill limits.
Open calculation →07Ohm’s law
Calculate current and power from voltage and resistance.
Open calculation →08Box fill
Check common insulated conductors, yokes, clamps, and equipment grounds.
Open calculation →0930° offset layout
Estimate travel and shrink for a 30-degree two-bend offset.
Open calculation →10Transformer full-load current
Three-phase current chart at 208, 240, and 480 V, plus a custom single- or three-phase calculation.
Open calculation →These worksheets are study aids. Check the adopted NEC edition, equipment instructions, and local amendments before using a result for design or installation.