Ohm’s Law Calculator
Ohm’s Law defines the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. Use this free online calculator to find any one value when the other two are known — ideal for students, technicians, and engineers.
Voltage, Current & Resistance Calculator
Enter any two known values — Voltage (V), Current (I), or Resistance (R).
Leave the third field blank.
Click Calculate to instantly find the missing value.
📘 How to Use
FAQ
What is Ohm’s Law?
Ohm’s Law states that voltage equals current times resistance (V = I × R).
How do I use this calculator?
Enter any two values for voltage, current, or resistance, then press calculate to find the third.
Can it handle all units?
This calculator works best with volts (V), amperes (A), and ohms (Ω). Make sure your inputs use these units.
Is it free to use?
Yes, the calculator is completely free for engineers and students.
Does it save results?
No, results are shown instantly but not stored on the site.
Can I use it offline or on mobile?
The calculator works on mobile browsers but requires internet to load the page; offline use isn’t supported.