Free · Physics models
RMS Apparent and Real Electrical Power
Relate RMS voltage, current, apparent power and power factor for one or three phases.
- Formula & worked example
- Private in your browser
- No signup
Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
kva1P = 2.4000; realPower 1P = 1.9200. This worked example uses the displayed units and declared assumptions.
kva1P = current * voltage / 1000; powerFactor = realPower_1P / kva1P; kva3Pll = sqrt(3) * current * voltage / 1000; powerFactor = realPower_3Pll / kva3Pll; kva3Pln = 3 * current * voltage / 1000; powerFactor = realPower_3Pln / kva3Pln
Worked example
Enter these known values and leave the other values blank.
- Load distribution
- 0
- Current (I)
- 10 A
- Voltage (V)
- 240 V
- Power factor
- 0.8
- Apparent power (S)
- 2.4 kVA
- Real power (P)
- 1.92 kW
Assumptions and limitations
- Three-phase relations assume balanced sinusoidal loads. Select line-to-line or line-to-neutral voltage consistently. Real power is apparent power multiplied by power factor, with no motor or generator efficiency correction.
- Clear an unknown to solve a supported inverse; keep known values fixed with locks. Singular or underdetermined inverses may remain incomplete.
Common questions
What assumptions apply?
Three-phase relations assume balanced sinusoidal loads. Select line-to-line or line-to-neutral voltage consistently. Real power is apparent power multiplied by power factor, with no motor or generator efficiency correction.
Which unknowns can I solve?
Editable controls preserve the supported captured inverse branches. Clear the desired unknown and provide enough independent known quantities; singular or underdetermined inverses may remain incomplete.
References
Use positive RMS voltage for the finite power-factor inverse. Use positive RMS current for the finite power-factor inverse. Replace example-note option accessors by their pinned numeric selector values, preserving the exact visibility predicates.