Power relationships
P = V × I, P = I² × R and P = V² / R are equivalent for a resistive load.
Power
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Electrical Power Calculator
Calculate DC power from voltage, current or resistance using P = VI, P = I²R and P = V²/R.
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Choose the pair of quantities you have and get real power in watts.
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Assumptions and limits.
- DC or resistive AC load.
Frequently asked questions
Is this real or apparent power?
This is real power for a DC or purely resistive load. For AC loads with reactance use the AC power calculator.