Ohm's Law
Calculate voltage, current, or resistance instantly with this free Ohm's law calculator. Includes clear formulas and step-by-step working for circuit problems.
Key formula
V = IR
About this tool
Ohm's law is one of the fastest ways to understand basic circuit behavior because it shows how voltage, current, and resistance constrain one another. This page helps users study that relationship without needing to rearrange the equation manually each time.
How to use this calculator
- Choose the variable you want to solve for and confirm which values are already known.
- Enter inputs in consistent units before calculating so the formula is applied correctly.
- Check whether the result is physically reasonable by comparing it with the size of the inputs.
- Use the step-by-step breakdown to see how the equation was rearranged and evaluated.