Electrical calculators
Watts, amps, volts, kVA and energy cost. 41 tools.
Amps to kVAConvert amps to kilovolt-amps for single-phase and three-phase supplies — apparent power, so no power factor is needed.Amps to kWConvert amps to kilowatts for DC, single-phase and three-phase circuits. Enter current, voltage and power factor to read real power in kW.Amps to VAConvert amps to volt-amps for single-phase and three-phase circuits. Apparent power in VA is current times voltage — power factor does not apply.Amps to VoltsConvert amps to volts with Ohm's law, V = I × R. Enter the current and the resistance to get the voltage across the component.Amps to WattsConvert amps to watts for DC, single-phase and three-phase circuits. Enter the current and the voltage to get real power in watts.Electricity billWork out what an appliance costs to run per day, month and year from its wattage, hours of use and your tariff.Energy Consumption CalculatorWork out how much energy an appliance uses per day, month and year from its wattage and how many hours a day you run it.Energy Cost CalculatorTurn an appliance's wattage and daily run time into a real cost per day, month and year at your own price per kilowatt-hour.eV to VoltsConvert electron-volts to volts by dividing the energy by the charge in elementary charges. Useful in physics and semiconductor work.Joules to VoltsConvert joules to volts by dividing the energy by the charge in coulombs — one volt is one joule per coulomb.Joules to WattsConvert joules to watts by dividing the energy by the time in seconds — the average power delivered over that interval.kVA to AmpsConvert kVA to amps for single-phase and three-phase supplies — the standard way to size cables and breakers from a transformer or generator rating.kVA to kWConvert apparent power in kVA to real power in kilowatts by multiplying by the power factor. Shows the working and the reactive power too.kVA to VAConvert kilovolt-amps to volt-amps. The kilo prefix is a factor of 1000, so the conversion is exact and the power factor is irrelevant.kVA to WattsConvert kVA to watts: multiply the apparent power by the power factor, then by 1000. Gives the real power the load actually consumes.kW to AmpsConvert kilowatts to amps for DC, single-phase and three-phase supplies — the quickest way to size a breaker or a cable from a motor rating.kW to kVAConvert real power in kilowatts to apparent power in kVA by dividing by the power factor — the number you need when sizing a generator.kW to kWhConvert kilowatts to kilowatt-hours by multiplying the power by the running time — power is a rate, energy is the rate times hours.kW to VAConvert kilowatts to volt-amps: divide by the power factor and multiply by 1000. Shows the substitution so you can check it by hand.kW to VoltsFind the supply voltage from a kilowatt rating and the measured current, for DC, single-phase and three-phase circuits.kWh to kWConvert kilowatt-hours to kilowatts by dividing the energy used by the number of hours it took — the average power draw over that period.kWh to WattsConvert kilowatt-hours to watts: divide the energy by the time in hours and multiply by 1000 to get the average power in watts.Ohm's lawEnter any two of voltage, current, resistance or power and get the other two instantly, with the formula used shown.Power CalculatorCalculate electrical power from voltage and current, and see the equivalent resistance, energy per hour and power in kilowatts.Power Factor CalculatorWork out power factor from real power and apparent power, and see the phase angle and the reactive power that goes with it.VA to AmpsConvert volt-amps to amps for single-phase and three-phase supplies — useful for sizing UPS output cables and transformer secondaries.VA to kVAConvert volt-amps to kilovolt-amps by dividing by 1000. An exact conversion — no power factor and no phase assumptions involved.VA to kWConvert volt-amps to kilowatts by multiplying by the power factor and dividing by 1000 — apparent power to real power in one step.VA to WattsConvert volt-amps to watts by multiplying by the power factor. On a purely resistive load the two are equal; on a motor they are not.Voltage dividerCalculate the output voltage of a two-resistor divider, or find the resistor you need to hit a target voltage.Volts to AmpsConvert volts to amps using resistance — Ohm's law, I = V ÷ R. Enter the voltage and the resistance to get the current in amps.Volts to eVConvert volts to electron-volts by multiplying by the charge in elementary charges — the energy an electron gains crossing that potential.Volts to JoulesConvert volts to joules using the charge in coulombs. Voltage is energy per unit charge, so energy equals voltage times charge.Volts to kWConvert volts to kilowatts using the circuit current and power factor, for DC, single-phase and three-phase supplies.Volts to WattsConvert volts to watts using the circuit current. Covers DC, single-phase and three-phase supplies and shows the calculation step by step.Watts to AmpsConvert watts to amps for DC, single-phase and three-phase supplies. Enter the power and the voltage and read the current, with the working shown.Watts to JoulesConvert watts to joules by multiplying the power by the time in seconds. A watt is one joule per second, so the conversion is exact.Watts to kVAConvert watts to kVA by dividing the real power by the power factor and by 1000 — the figure to quote when specifying a UPS or generator.Watts to kWhConvert watts to kilowatt-hours: multiply the power by the hours it runs and divide by 1000. This is the number your electricity bill charges for.Watts to VAConvert watts to volt-amps by dividing by the power factor. The result is the apparent power a supply must be able to deliver.Watts to VoltsWork out the supply voltage from power and current for DC, single-phase and three-phase circuits, with the formula and the substitution shown.