Ohm's Law - Calculate Resistance

Calculator for electrical resistance, voltage and amperage, with different units. Ohm's law states that resistance is voltage divided by amperage. The formula is R=U/I, the unit is ohm, its symbol is the omega, Ω=V/A. Electrical resistance is a measure of the impediment to the flow of current in an electrical conductor. The lower the resistance, the better the current conducts.

Please select the units and enter two values. The third value will be calculated.

Voltage U:
Amperage I:
Resistance R:

Example: if there is a voltage of 240 volts and a current flow of 3 amperes, then the resistance is 80 ohms.

Physics commonly uses SI units. Here is a calculator to convert units.