PhysRefPhysics reference
Electricity & Magnetism
P=IV=I2R=V2RP = IV = I^2R = \frac{V^2}{R}

Power dissipated in circuit element.

Variables

P
Power
Rate of energy transfer
In SI units: kg·m²/s³
Allowed values: greater than 0
W
I
Current
Electric current
A
V
Voltage
Potential difference
In SI units: kg·m²/(A·s³)
V
R
Resistance
Electrical resistance
In SI units: kg·m²/(A²·s³)
Allowed values: 0 or more
Ω

Derivation

P = dW/dt = V(dq/dt) = VI. Use Ohm's law for other forms.

Your notes

0/5000

Check value

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  • I = 2 A (Current)
  • V = 3 V (Voltage)

Result: P = 6 W

Other electricity & magnetism formulas with the same quantities

Where this formula is listed

Common questions

What is the Electric Power formula?

Electric Power is written P = IV = I²R = V²/R. Power dissipated in circuit element. It belongs to Electricity & Magnetism, under Electric Circuits.

What are the units in P = IV = I²R = V²/R?

In SI units, P is power, measured in kg·m²/s³; I is current, measured in A; V is voltage, measured in kg·m²/(A·s³); R is resistance, measured in kg·m²/(A²·s³).

How is the Electric Power formula derived?

P = dW/dt = V(dq/dt) = VI. Use Ohm's law for other forms. The result is P = IV = I²R = V²/R.