⚡ Ohm’s Law Calculator
Enter values for any two of the four fields — the rest are calculated automatically.
Voltage12 V
Current3 A
Resistance4 Ω
Power36 W
Enter any two known values among voltage (V), current (A), resistance (Ω), and power (W), and this tool automatically calculates the remaining two using Ohm’s law (V=IR) and the power formula (P=VI).
How to use
- Enter values for any two of the four fields (voltage, current, resistance, power).
- The other two fields are calculated automatically.
- If you enter more than two, the first two in order (voltage, current, resistance, power) are used.
FAQ
Can I use any combination of two values?
Yes. Voltage and current, voltage and resistance, current and resistance, voltage and power — any two of the four fields can be used.
What formulas does this use?
It combines Ohm’s law (V = I × R) with the power formula (P = V × I) to derive the remaining two values from any two known values.
What happens if I enter more than two values?
Only the first two values, in the order voltage, current, resistance, power, are used for the calculation — the rest are ignored. Note that inconsistent values are not flagged.