Single and Three Phase AC Power Calculator
Calculate apparent, real and reactive power for a single-phase or balanced three-phase load with an explicit RMS voltage convention.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Convert voltage and current to SI. Apply the selected phase/voltage multiplier, then resolve apparent power into real and reactive magnitudes with the entered power factor.
Single phase: S=VI; balanced three phase: S=√3 VLL I or 3 VLN I; P=S·PF; |Q|=S√(1−PF²)
Worked example
A balanced 400 V line-to-line, 10 A, 0.8 PF load has S≈6.928 kVA, P≈5.543 kW and |Q|≈4.157 kvar.
Assumptions and input details
RMS sinusoidal steady-state model. Three-phase results assume balanced phases and the current paired with the selected voltage convention. Power factor is a magnitude only, so leading/lagging sign is not inferred. Energy is arithmetic real power times entered hours. Do not use this page to select wiring, protection or equipment ratings.
References: Fluke: balanced three-phase AC power · Fluke: power factor
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
SI prefixes are explicit: for example, milli means one thousandth, micro one millionth and kilo one thousand. Changing a unit changes the interpretation of the entered number.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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