What is it?
The Electrical Power Calculator works out how much power a device or circuit uses. It shows watts and kilowatts, apparent power (VA), horsepower and the electricity units used in one hour.
Who is it for?
Electricians, students, and anyone sizing generators, UPS units or checking motor power.
How to use it
Choose the Supply: DC, Single-phase AC or Three-phase AC. Enter Voltage, Current and the Power factor (1 for heaters and bulbs; 0.8–0.9 for motors). The answer appears as you type; there is no Calculate button. Tap Copy result to copy it, or Share on WhatsApp to send it.
Formulas
DC: P = V × I. Single phase: P = V × I × PF. Three phase: P = √3 × V × I × PF (V is the line-to-line voltage). 1 HP = 746 W. In India, three-phase line voltage is 400–415 V; single phase is 230 V.
kW vs kVA
- kW is real power that does work and is billed on your meter.
- kVA is apparent power: what the wiring, inverter or generator must carry. Size generators and UPS units in kVA.
- A 5 kW motor with PF 0.8 needs 6.25 kVA.
Units on your bill
kW × hours = units (kWh). For monthly cost, use the Electricity Bill Calculator.
Electrical work can kill. Use these numbers for planning and learning; have a licensed electrician do and check any wiring, following your local wiring rules.
Errors and how to fix them
- “Power factor is between 0 and 1”: use 1 for heaters and 0.8 for motors.
Open the tool: Electrical Power Calculator
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.