AllEasyToolsUpper secondary
Ohm’s law and power
Ohm’s law and power: formula, units and explained result. No account required. Processing stays in your browser.
I = V/R; P = VI
Positive resistance, ideal resistive circuit.
How to use this calculator
- Identify the quantities and convert them to the units shown.
- Apply the formula first, then compare with the substitution and result.
- Check the assumptions and whether the order of magnitude makes sense.
Levels are approximate topic groupings, not a complete curriculum for every country. Numerical results are rounded and may lose precision for extreme or nearly singular inputs.
A practical example
Use these sample inputs to check the calculation before entering your own values.
- Voltage (V)
- 12
- Resistance (Ω)
- 6
Result for this example
- Current
- 2 A
- Power
- 24 W