Electrical Power Calculator
Enter voltage and current to compute electrical power P = V·I instantly.
Input Data
Results
At a glance:Electrical power P is the rate of electrical energy transfer, P = V·I (volts × amperes = watts). For a resistor, this equals I²·R = V²/R (Joule heating). In AC circuits the instantaneous product V(t)·I(t) averaged over a cycle gives real power; apparent power is V_rms·I_rms and reactive power involves the phase. This tool uses the direct DC/real-power relation P = V·I.
Formula
P = V·I
Resistive: P = I²·R = V²/R
$$P = V \times I$$How to Use
- Enter the voltage V (V).
- Enter the current I (A).
- The calculator returns the power P = V·I.
Case Studies
Appliance load
Device draws 8 A at 230 V.
P = 230×8 = 1840 W.
A 2 kW breaker is appropriate with margin.
FAQ
Is this for DC or AC?
P = V·I gives real power for DC and for resistive AC loads in phase. For AC with a phase angle φ use P = V·I·cosφ (cosφ = power factor).
How do I size a breaker?
Choose a breaker rated above the operating current with margin; power tells you the current for a given voltage (I = P/V).
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References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.