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AC power & reactance calculators
Calculate sinusoidal AC quantities, power factor and balanced three-phase power.
Choose the right calculation
Use RMS values in the AC power relationships. Apparent power is measured in VA and real power in watts. Pure-sine conversions and balanced three-phase equations only apply under their stated assumptions.
Find a tool for your question
Capacitive Reactance Calculator
Find capacitor reactance magnitude at a given sinusoidal frequency.
Inductive Reactance Calculator
Find ideal inductor reactance magnitude for sinusoidal AC.
LC Resonant Frequency Calculator
Find the ideal natural resonant frequency of an LC circuit.
AC Apparent Power Calculator
Calculate apparent power from single-phase RMS voltage and current.
Power Factor Calculator
Calculate real power divided by apparent power.
Three Phase Power Calculator
Estimate balanced three-phase real power from line voltage and line current.
RMS Sine Voltage Calculator
Convert peak amplitude of a pure sine wave to RMS voltage.
Single Phase AC Current Calculator
Find single-phase RMS current from real power, voltage and power factor.
Three Phase Current Calculator
Find line current for a balanced three-phase real-power load.
Reactive Power Calculator
Find reactive-power magnitude from compatible apparent and real power.
Power Factor Angle Calculator
Convert a sinusoidal displacement power factor into phase-angle magnitude.
Power Factor Correction Calculator
Estimate reactive compensation needed to raise an entered displacement power factor.
Series RLC Impedance Calculator
Find impedance magnitude for a series RLC circuit from component reactances.
Series RLC Phase Angle Calculator
Find the ideal voltage-current phase angle of a series RLC impedance.
RC Low Pass Cutoff Calculator
Find the minus-three-decibel cutoff of an ideal RC low-pass filter.
RL Filter Cutoff Calculator
Find the characteristic cutoff frequency of a simple RL filter.
Decibel Power Ratio Calculator
Express a power ratio as a decibel difference.
Decibel Voltage Ratio Calculator
Express a voltage amplitude ratio as a decibel difference.
Decibels to Power Ratio Calculator
Recover a linear power ratio from a decibel difference.
Decibels to Voltage Ratio Calculator
Recover a voltage amplitude ratio from a decibel difference.
Motor Synchronous Speed Calculator
Find synchronous rotating-field speed from frequency and pole count.
Induction Motor Slip Calculator
Compare rotor speed with a synchronous reference speed.
Motor Shaft Torque Calculator
Find shaft torque from mechanical power and rotational speed.
Transformer Secondary Current Calculator
Find ideal transformer secondary current from current and turns ratio.
Why can volt-amps differ from watts?
Apparent power is the RMS voltage-current product, while real power also reflects power factor. They are numerically equal only at a power factor of one.
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