⚡ Ohm's Law Calculator
Enter any two of voltage, current, resistance, or power to calculate the rest
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Enter valid values to start calculating
Enter any two of voltage, current, resistance, or power to calculate the rest
Enter valid values to start calculating
This calculator computes voltage, current, resistance, and power using Ohm's Law. Enter any two known values and it automatically calculates the other two.
Ohm's Law is the most fundamental law in electricity, widely applied in circuit design, electrical repair, and physics education.
Basic formulas: - U = I × R (Voltage = Current × Resistance) - I = U / R (Current = Voltage / Resistance) - R = U / I (Resistance = Voltage / Current)
Power formulas: - P = U × I (Power = Voltage × Current) - P = I^2 × R (Power = Current^2 × Resistance) - P = U^2 / R (Power = Voltage^2 / Resistance)
Common electrical references: - US household voltage: 120V - EU/Asia household voltage: 220-240V - Phone charger: 5V/2A = 10W - Electric kettle: 220V/1500W → I≈6.8A, R≈32.3Ω - LED bulb: 220V/10W → I≈0.045A, R≈4840Ω