Power & Current Electrical Calculators
Use our free power and current calculators to calculate watts, amps, volts, kW, kVA, VA, power factor, resistance, and other common electrical values. Choose from DC, single-phase AC, three-phase AC, power conversion, and current conversion tools.
Featured Power Calculators
Start with these general electrical calculators for common power, current, resistance, and power factor calculations.
Electrical Power Calculator
Calculate watts, kilowatts, VA, and kVA for DC, single-phase AC, and balanced three-phase AC electrical systems.
Open Electrical Power Calculator →Ohm's Law Calculator
Calculate voltage, current, resistance, and watts from any two known electrical values using Ohm's Law.
Open Ohm's Law Calculator →Power Factor Calculator
Calculate power factor from real power and apparent power using watts and VA or kilowatts and kVA.
Open Power Factor Calculator →Single-Phase Power Calculator
Calculate watts, kW, VA, and kVA from voltage, current, and power factor for a single-phase AC system.
Open Single-Phase Calculator →Three-Phase Power Calculator
Calculate real and apparent power for a balanced three-phase electrical system using line-to-line voltage and line current.
Open Three-Phase Calculator →Current Conversion Calculators
Convert electrical power to current or current to electrical power using voltage, phase, and power factor where required.
kVA to Amps Calculator
Convert apparent power in kVA to current for single-phase and three-phase electrical systems.
Calculate kVA to Amps →Amps to kVA Calculator
Calculate apparent power in kVA from current and voltage for single-phase and three-phase systems.
Calculate Amps to kVA →kW to Amps Calculator
Convert real power in kilowatts to current using voltage, phase, and power factor.
Calculate kW to Amps →Amps to kW Calculator
Convert electrical current to real power in kilowatts for single-phase and three-phase AC systems.
Calculate Amps to kW →Watts to Amps Calculator
Convert watts to electrical current for DC, single-phase AC, and three-phase AC systems.
Calculate Watts to Amps →Amps to Watts Calculator
Convert amps to watts using voltage and, for AC systems, power factor.
Calculate Amps to Watts →VA to Amps Calculator
Convert apparent power in volt-amperes to current using voltage and electrical phase.
Calculate VA to Amps →Amps to VA Calculator
Calculate apparent power in VA from electrical current and voltage.
Calculate Amps to VA →Power Conversion Calculators
Convert between watts, VA, kW, and kVA using power factor where required.
kVA to kW Calculator
Convert apparent power in kVA to real power in kilowatts using power factor.
Calculate kVA to kW →kW to kVA Calculator
Convert real power in kilowatts to apparent power in kVA using power factor.
Calculate kW to kVA →kVA to Watts Calculator
Convert kVA to watts using apparent power and power factor.
Calculate kVA to Watts →Watts to kVA Calculator
Convert watts of real power to apparent power in kVA using power factor.
Calculate Watts to kVA →Watts to VA Calculator
Convert real power in watts to apparent power in volt-amperes using power factor.
Calculate Watts to VA →VA to Watts Calculator
Convert apparent power in VA to real power in watts using power factor.
Calculate VA to Watts →Common Electrical Power Formulas
Understanding Power and Current Calculations
Electrical power and current calculations are commonly used when working with electrical equipment, appliances, UPS systems, generators, motors, power supplies, electrical panels, data center equipment, lighting, audio and video equipment, and other electrical loads.
The correct formula depends on the type of electrical system and the values you already know. DC systems normally use voltage and current directly. AC real-power calculations may also require power factor, while balanced three-phase calculations using line-to-line voltage include the √3 factor.
VoltCalculators provides separate calculators for common conversions so you can choose the exact tool that matches the electrical values available to you.
Frequently Asked Questions
What is the basic electrical power formula?
For a DC circuit, electrical power is calculated as Watts = Volts × Amps.
How do I calculate amps from watts?
For DC, divide watts by volts. For AC systems, the calculation may also require power factor and, for three-phase systems, the √3 factor.
What is the difference between kW and kVA?
kW represents real power, while kVA represents apparent power. Their relationship depends on power factor.
kW = kVA × Power Factor
What is the difference between watts and VA?
Watts represent real power that performs useful work. VA represents apparent power in an AC electrical system.
Does power factor affect current?
Yes. When calculating AC current from real power, a lower power factor generally requires more current for the same amount of real power.
What formula is used for single-phase power?
Real power is calculated as Watts = Volts × Amps × Power Factor.
What formula is used for three-phase power?
For a balanced three-phase system using line-to-line voltage, real power is calculated as Watts = √3 × Volts × Amps × Power Factor.
What is Ohm's Law?
Ohm's Law describes the relationship between voltage, current, and resistance.
Voltage = Current × Resistance
Which calculator should I use if I am not sure?
Start with the Electrical Power Calculator if you know voltage and current and want to calculate electrical power. Use the Ohm's Law Calculator when working with voltage, current, resistance, and watts.
