Electrical calculators
Power & Energy Calculators
24 tools
Watts, VA, kVA, power factor, transformers, and energy use.
Popular in Power & Energy
Featured tools from the Family registry.
- Electric Power Calculator Calculate electrical power in watts from voltage and current for DC, single-phase AC, or balanced three-phase AC, from current and resistance, or from energy over time.
- Watts to Amps Calculator Convert watts to amps (and reverse) for DC, single-phase, and three-phase circuits. Power factor and voltage inputs included for AC loads. Try it free.
- Power Factor Calculator Calculate power factor from real power, voltage, and current for single-phase and three-phase (line-line or line-neutral) circuits. Try it free.
- Amps to VA Calculator Convert amps and volts to apparent power in VA or kVA for single-phase and three-phase circuits. Also convert VA back to amps. Fast and free.
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- Amps to kW Calculator Convert amps and volts to real power in kW for DC, AC single-phase, and balanced AC three-phase line-to-line. Runs locally in your browser. Free online tool — no sign-up.
- Amps to VA Calculator Convert amps and volts to apparent power in VA or kVA for single-phase and three-phase circuits. Also convert VA back to amps. Fast and free.
- Amps to Volts Calculator Solve voltage from current and resistance or power using Ohm’s law and P = V × I. Supports resistive DC and RMS AC estimates with clear formulas.
- Electric Power Calculator Calculate electrical power in watts from voltage and current for DC, single-phase AC, or balanced three-phase AC, from current and resistance, or from energy over time.
- Energy Consumption Calculator Estimate energy use in kWh from device watts and hours of operation. Useful for appliance and load planning. Runs locally in your browser. Try it free.
- Energy Cost Calculator Estimate electricity usage cost from watts/hours or kWh and your unit rate. Supports custom billing periods; standing charges and taxes are excluded. Runs locally in your browser.
- eV to Volts Calculator Relate electronvolt energy to electric potential difference through ΔE = qΔV. eV and volts measure different physical quantities. Runs locally in your browser.
- kVA to Amps Calculator Convert kVA and voltage to line current for single-phase and three-phase systems. Uses √3 for three-phase line-to-line volts. Runs locally in your browser.
- kVA to kW Calculator Convert apparent power (kVA) to real power (kW) with power factor. States when PF is required and when loads are assumed balanced. Try it free.
- kW to VA Calculator Convert kilowatts to volt-amperes using power factor. Distinguishes real vs apparent power for feeder and transformer sizing. Runs locally in your browser.
- kWh to kW Calculator Convert kilowatt-hours and duration into average kilowatts. Clarifies energy vs power for metering and solar sizing. Runs locally in your browser.
- kWh to Watts Calculator Convert energy in kWh and a time period into average power in watts (and reverse) for load and generation estimates. Runs locally in your browser.
- Power Factor Calculator Calculate power factor from real power, voltage, and current for single-phase and three-phase (line-line or line-neutral) circuits. Try it free.
- Transformer Sizing Calculator Ideal transformer: Vp/Vs=Np/Ns, currents, and VA = V·I. First-pass sizing. Runs locally in your browser.
- VA to kVA Calculator Convert volt-amperes (VA) to kilovolt-amperes (kVA) with the exact 1000× scale factor used on nameplates. Runs locally in your browser. Try it free.
- Voltage Drop Calculator Estimate DC or resistive single-phase / balanced three-phase voltage drop and conductor I²R loss from current, cable length, and Ω/km. Optional system voltage shows % drop and load voltage. Runs locally in your browser. Try it free.
- Volts to Joules Calculator Relate voltage, charge, or capacitance to energy in joules for electrostatic and capacitor examples. Runs locally in your browser. Try it free.
- Volts to kW Calculator Estimate kilowatts from voltage, current, and power factor for single-phase and three-phase circuits. Runs locally in your browser. Try it free.
- Watts to Amps Calculator Convert watts to amps (and reverse) for DC, single-phase, and three-phase circuits. Power factor and voltage inputs included for AC loads. Try it free.
- Watts to Joules Calculator Convert watts and time to energy in joules (and reverse). Shows W × s = J with worked timing examples. Runs locally in your browser. Try it free.
- Watts to kVA Calculator Convert watts to kVA with power factor. Helps size generators and UPS equipment from real power demand. Runs locally in your browser. Try it free.
- Watts to VA Calculator Convert real power in watts to apparent power in VA using power factor. Clarifies W vs VA for sizing breakers and transformers. Try it free.
- Watts to Volts Calculator Find voltage from power and current (or resistance). Useful for DC and resistive AC checks with unit guidance. Runs locally in your browser.
- Watts Volts Amps Calculator Solve any two of watts, volts, amps, and ohms for the other values—an Ohm’s-law style watt–volt–amp workspace. Runs locally in your browser.