What is the Electrical Power Calculator?
Calculate electrical power in watts from voltage and current. These physics and science calculators apply standard SI formulas with exact constants (such as g = 9.80665 m/s² and the 2019 SI definitions) for students, engineers and curious minds.
How to use the Electrical Power Calculator
- Enter your voltage, your current, your power factor.
- Results update automatically as you type; you can also press Calculate.
- Read the output: power, in kw, apparent power.
- Use the 📊 chart to see the result visually, then copy or share it.
Formula and method
Worked example
With voltage = 120 V, current = 10 A, power factor = 1, the Electrical Power Calculator returns power: 1,200.00 W; in kw: 1.200 kW; apparent power: 1,200.00 VA.
Tips for better results
- Convert inputs into SI units first for the cleanest results.
- Idealized formulas ignore friction and air resistance unless stated.
- Use our unit converters to switch between metric and imperial results.
Frequently asked questions
What does the Electrical Power Calculator do?
Calculate electrical power in watts from voltage and current.
How is it calculated?
The Electrical Power Calculator uses this method: P = V × I × PF.
Can you show an example?
With voltage = 120 V, current = 10 A, power factor = 1, the Electrical Power Calculator returns power: 1,200.00 W; in kw: 1.200 kW; apparent power: 1,200.00 VA.
Is the Electrical Power Calculator accurate?
Yes. It uses standard formulas and exact constants, and the results are verified by our automated test suite. Values are displayed to up to 12 significant digits.
Is this tool free and private?
Yes — the Electrical Power Calculator is completely free with no sign-up, and it runs entirely in your browser, so the values you enter are never uploaded to our servers.
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