What Is an Ohm’s Law Calculator?
An Ohm’s Law Calculator is an electrical tool used to determine voltage, current, resistance, or power in a circuit. It applies the mathematical relationship between volts, amperes, ohms, and watts.
Instead of rearranging several formulas manually, you can enter any two known electrical values. The calculator automatically determines the other two values and displays the correct units.
How to Use the Ohm’s Law Calculator
You only need two known values to calculate the complete electrical relationship.
Enter Two Values
Enter any two known values, such as voltage and resistance.
Calculate
Select the Calculate Values button to process the electrical formulas.
Review Results
View voltage, current, resistance, power, and the formula used.
Ohm’s Law Formulas
The calculator combines Ohm’s Law with standard electrical power formulas.
| Calculate | Formula | Unit | Meaning |
|---|---|---|---|
| Voltage | V = I × R | Volts (V) | Electrical potential difference |
| Current | I = V ÷ R | Amperes (A) | Flow of electric charge |
| Resistance | R = V ÷ I | Ohms (Ω) | Opposition to current flow |
| Power | P = V × I | Watts (W) | Rate of electrical energy usage |
Ohm’s Law Calculation Example
Suppose a circuit has a voltage of 12 volts and resistance of 6 ohms.
Calculate the Current
Current = Voltage ÷ Resistance
Current = 12 ÷ 6 = 2 amperes
Calculate the Power
Power = Voltage × Current
Power = 12 × 2 = 24 watts
Frequently Asked Questions
Ohm’s Law describes the relationship between voltage, current, and resistance. Its main formula is V = I × R.
Enter exactly two known values from voltage, current, resistance, and power. The calculator will determine the remaining values.
Divide voltage by resistance. For example, a 12-volt circuit with 6 ohms of resistance has a current of 2 amperes.
Yes. It calculates electrical power in watts using values such as voltage and current, current and resistance, or voltage and resistance.
The Ω symbol represents ohms, which is the standard measurement unit for electrical resistance.
Ohm’s Law works directly for ohmic components whose resistance remains stable. Some components, such as diodes and certain lamps, may have nonlinear electrical behavior.