Ohm's Law Calculator
Enter values to see results
Free Ohm's Law Calculator & Watt's Law Calculator
Whether you are an electrical engineering student, a licensed electrician, or a DIY hobbyist, solving electrical circuits requires precision. Our professional Ohm's Law Calculator seamlessly integrates Watt's Law, allowing you to quickly determine Voltage (V), Current (I), Resistance (R), and Power (P) by simply entering any two known variables.
[Image of Ohm's Law pie chart formula wheel]How to Use the Calculator
- Select Your Knowns: Use the dropdown menu at the top to select the two electrical parameters you already know. For example, if you know the circuit's Voltage and Resistance, select "Voltage (V) & Resistance (R)".
- Enter Your Values: Type your numbers into the two dynamically generated input boxes.
- Adjust Your Units: Use the adjacent dropdowns to define your metric prefixes. The calculator flawlessly handles milli (m), micro (µ), kilo (k), and Mega (M) conversions instantly.
- View Instant Results: There is no need to hit calculate! Your missing variables are calculated in real-time. The calculated answers will be highlighted in green to differentiate them from the numbers you manually entered.
The Core Formulas
This tool relies on the foundational formulas of DC electricity:
- Voltage (V) = Current (I) × Resistance (R)
- Current (I) = Voltage (V) / Resistance (R)
- Resistance (Ω) = Voltage (V) / Current (I)
- Power (W) = Voltage (V) × Current (I)
Educational Disclaimer: The results provided by this calculator represent ideal, theoretical DC (Direct Current) circuits based on standard Ohm's Law. Real-world AC (Alternating Current) circuits involve complex impedance, phase angles, and power factors that this basic calculator does not account for. Always use proper safety equipment and consult a licensed professional before working on live electrical systems.