Ohm's Law Calculator
Calculate Voltage (V), Current (I), Resistance (R), and Power (P)
An Ohm's law calculator finds voltage, current, resistance, or power from the two values you enter, using V = I × R and P = V × I.
Calculator Inputs
See label below based on selection
See label below based on selection
Results
Enter values above to see your results
How It Works
V = I × R (Voltage = Current × Resistance). Power (P) = V × I.
Worked example
Voltage from 2 A and 10 Ω
Solve For:
Voltage (V)= Value 1 is current, Value 2 is resistanceValue 1:
2 A= CurrentValue 2:
10 Ω= ResistanceVoltage:
V = I × R = 2 × 10= 20.0000 VPower:
P = V × I = 20 × 2= 40.00 WTips & Best Practices
- •Enter any two known values to find the others.
- •Remember to convert units (e.g., mA to A) before calculating, or use the base units (Volts, Amps, Ohms).
Frequently Asked Questions
What is Ohm's Law?
It states that the current through a conductor is directly proportional to the voltage across it.
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