Electrical Engineering Calculators

Solve for any of the four fundamental electrical quantities given any two known values.

Calculate active, reactive, and apparent power in balanced 3-phase AC systems.

Compute terminal voltage and percentage drop for conductors over any distance.

Decode resistor color bands to find resistance value, tolerance, and E-series.

Solve voltage dividers for output voltage, required R2, or input voltage.

Calculate equivalent resistance and total current for parallel resistor networks.

Convert between AWG gauge, mm² cross-section, and diameter with ampacity data.

Size conductors by ampacity and voltage drop constraints for copper and aluminium cables.

Calculate 3-phase fault current at transformer secondary from impedance.

Size capacitor banks in kVAR to correct power factor to a target value.

Calculate primary and secondary full-load currents from transformer kVA rating.

Size kVAR banks to raise power factor and reduce utility penalty charges.

Size copper or aluminium busbars for continuous current and temperature rise.

Calculate earth electrode resistance for rods, strips, and plates.

Calculate maximum demand with load group demand factors and diversity.

Calculate total harmonic distortion (THD) and check IEEE 519 compliance.

Find full-load amperes for three-phase and single-phase motors.

Convert between shaft power, torque, and speed for electric motors.

Calculate inrush current for DOL, star-delta, auto-transformer, and VFD starts.

Calculate motor input power, output power, efficiency, or load percentage.

Convert VFD output frequency to motor shaft speed, accounting for slip.

Select correct circuit breaker rating and type for motors and general loads.

Size contactors for motor starting applications per IEC 60947-4-1.

Calculate IDMT relay pickup, TMS, and trip time for SI, VI, EI curves.

Calculate current and voltage transformer ratios and scale secondary readings.

Convert 4-20mA signals to process values, percentages, and ADC counts.

Convert PT100 resistance and temperature using Callendar-Van Dusen equations.

Size generators based on demand factor, inrush, and design margin.

Calculate battery Ah for required backup time with DoD and efficiency.

Calculate daily, monthly, and annual electricity bills with PF penalty warning.