Ohm's Law Calculator
Calculate voltage, current, resistance, and power.
Circuit Parameters
Volts
Amperes
Ohms (Ω)
Watts
Calculated Values
Voltage (V)
0.000 V
Current (I)
0.000 A
Resistance (R)
0.000 Ω
Power (P)
0.000 W
Formulas Used:
Enter any two values to see the formulas used.
About This Calculator
Ohm's Law Calculator calculates voltage, current, resistance, and power in electrical circuits. Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance.
Enter any two values (voltage, current, resistance, or power), and the calculator will automatically calculate the remaining values. This is useful for electrical engineering, circuit design, and troubleshooting electrical problems.
Formula & Calculation Method
Ohm's Law Formulas:
Ohm's Law:
V = I × R
I = V ÷ R
R = V ÷ I
Power Formulas:
P = V × I
P = V² ÷ R
P = I² × R
Where:
V = Voltage (Volts)
I = Current (Amperes)
R = Resistance (Ohms)
P = Power (Watts)
Ohm's Law is a fundamental principle in electrical engineering. It describes the relationship between voltage, current, and resistance in an electrical circuit. Power can be calculated using any combination of voltage, current, and resistance.
How to Use This Calculator
- Enter Two Values: Input any two of the four values (voltage, current, resistance, power).
- Leave Others Empty: Leave the values you want to calculate empty.
- View Results: See the calculated values automatically displayed.
- Use Results: Use the calculated values for circuit design and analysis.
Frequently Asked Questions
What is Ohm's Law?
Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance. It is expressed as V = I × R, where V is voltage, I is current, and R is resistance.
How do I calculate power?
Power can be calculated using three formulas: P = V × I, P = V² ÷ R, or P = I² × R. Choose the formula based on which values you know (voltage and current, voltage and resistance, or current and resistance).
What units are used?
Voltage is measured in Volts (V), current in Amperes (A), resistance in Ohms (Ω), and power in Watts (W). These are the standard SI units for electrical measurements.
Can I use this for AC circuits?
Ohm's Law applies to DC (direct current) circuits and resistive AC circuits. For AC circuits with reactive components (inductors, capacitors), you need to use impedance instead of resistance and consider phase angles.
Calculator by
NumCalculators Editorial Team
Multi-disciplinary Expert Team