Real Power Calculator

Calculate watts for AC circuits with fast, accurate inputs. Compare phases, voltage, current, and frequency. Export results for reports and smarter electrical planning today.

Calculator Inputs

Enter line or phase voltage for the selected mode.
Use 1.00 for resistive or DC loads.
Used to estimate useful output power and heat loss.
Enter your currency cost per kWh.

Example Data Table

Case System Voltage Current PF Real Power
Office heater Single-phase 230 V 10 A 1.00 2,300 W
Workshop motor Three-phase 415 V 18 A 0.86 11,134 W
Server rack Single-phase 230 V 7.5 A 0.95 1,639 W
Battery charger DC 48 V 22 A 1.00 1,056 W

Formula Used

Single-phase AC: Real Power (W) = Voltage × Current × Power Factor

Three-phase AC: Real Power (W) = √3 × Line Voltage × Current × Power Factor

DC: Real Power (W) = Voltage × Current

Useful Output Power: Output Power = Input Real Power × Efficiency

Demand Adjusted Power: Demand Power = Input Real Power × Demand Factor

Daily Energy: Energy (kWh) = Real Power (kW) × Operating Hours

Reactive Power: Reactive VAR = √(Apparent Power² − Real Power²)

How to Use This Calculator

  1. Select the electrical system type first.
  2. Choose line or phase voltage for three-phase entries.
  3. Enter voltage, current, and power factor values.
  4. Add efficiency and demand factor for advanced analysis.
  5. Include hours and energy rate to estimate cost.
  6. Press the calculate button to show results above the form.
  7. Download CSV for spreadsheets or PDF for reports.

Engineering Notes

Real power is the portion of electrical power that performs useful work. It is measured in watts and depends on voltage, current, and power factor.

Apparent power reflects the total electrical demand on the source. Reactive power represents energy oscillation in inductive or capacitive circuits.

This calculator helps compare supply demand, useful output, cost impact, and losses across single-phase, three-phase, and DC systems.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.