Electrical Power Calculator — Watts, Volts & Amps
Calculate electrical power in watts from voltage and current. Supports DC, single-phase AC, and 3-phase AC systems.
About This Calculator
Computes power (watts) from voltage and current using the standard power formula, with support for DC, single-phase AC, and 3-phase AC (line-to-line voltage) including power factor.
About This Calculator
Computes power (watts) from voltage and current using the standard power formula, with support for DC, single-phase AC, and 3-phase AC (line-to-line voltage) including power factor.
Frequently Asked Questions
How do I calculate power in watts from volts and amps?
For DC or single-phase AC at unity power factor: Watts = Volts × Amps. For AC with a power factor below 1 (typical for motors and inductive loads), multiply by the power factor: Watts = Volts × Amps × Power Factor.
How is 3-phase power calculated?
For a balanced 3-phase system using line-to-line voltage: Watts = √3 × Volts × Amps × Power Factor (√3 ≈ 1.732). This is the standard formula used for 3-phase motors and industrial equipment.
What power factor should I use?
Use 1.0 (unity) for purely resistive loads like heaters. Real motors and industrial equipment typically have a power factor of 0.8–0.95 — check the equipment nameplate if you need an exact figure.
Is this an electrical power calculator or a math exponent calculator?
This is the electrical power calculator (watts from volts and amps). If you were looking for a math calculator that computes base raised to an exponent (like 2^10), that is a separate tool on CalcSphere.
Is this calculator free to use?
Yes — it is completely free to use online, with no sign-up required.