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Electronics reference tool
Ohm’s Law Calculator
Enter any two electrical values to calculate the remaining values instantly. The live circuit responds as voltage, current, resistance, and power change.
Did you know? Ohm’s law is named after German physicist Georg Simon Ohm, who published the relationship between voltage, current, and resistance in 1827 in his work on galvanic circuits.
Input values
Use any two fields. Leave the values you want calculated blank.
Enter any two values to begin.
Real-time circuit view
Flow speed and lamp brightness respond to calculated current and power.
Voltage—
Current—
Resistance—
Power—
How the result is calculated
Enter any two values above. The calculator will choose the appropriate Ohm’s Law or power formula and show each step here.
V = I x R
1Choose two known electrical values.
2Enter the values with their displayed units.
3Review the calculated results and the live circuit response.