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Ohm's Law Calculator
Calculate voltage, current, resistance, and power for a DC resistive circuit from two known electrical quantities.
- Voltage
- 12 V
- Current
- 2 A
- Resistance
- 6 Ω
- Power
- 24 W
How the calculation works
Ohm's law: V = IR. Power P = VI = I²R = V²/R. Select the known pair and enter values in volts, amperes, or ohms.
Inputs
- Known quantities
- First value (V or A)
- Second value (Ω or A)
Calculation details
At 12 V and 6 Ω, current is 2 A and power is 24 W. Divide milliamperes by 1,000 before entering them.
This uses positive magnitudes in an ideal DC resistive circuit. AC circuits containing reactive components require impedance and phase information.
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Updated: 2026-10-02