Formula
V = I × R. Power can be calculated with P = V × I, P = I² × R or P = V² ÷ R.
ELECTRONICS
Ohm's Law Calculator
Calculate voltage, current, resistance and power from two known values.
CALCULATOR GUIDE
How to use the Ohm's Law Calculator
Calculate voltage, current, resistance and power from two known values for basic DC circuit checks.
Worked example
A 12 V source across 6 Ω produces 2 A and 24 W in an ideal resistive circuit.
Assumptions and limits
This is an ideal DC model. AC impedance, tolerances, temperature and electrical safety require further analysis.
Frequently asked questions
Can I use this for household AC wiring?
Real AC systems introduce impedance, phase and safety requirements. Consult a licensed electrician.
Why allow extra resistor wattage?
Operating below the maximum rating reduces heat stress and improves reliability.
How this calculator works
Enter your known values and select Calculate result. Review units and inputs before relying on the planning estimate.
Actual quantities, prices and requirements can vary. Confirm critical work with a supplier or qualified professional.