Find amperage, voltage or resistance

This calculator will help you calculate the amperage (I), voltage (U) and resistance (R) in a circuit. The calculation is based on Ohm’s law. Select a value and calculate it according to known parameters.


Determine current

Voltage (U) Volt:
Resistance (R) Ohm:

Determine the resistance value

Voltage (U) Volt:
Amperage (I) Amp:

Find voltage

Current (I) Ampere:
Resistance (R) Ohm:

Definitions and formulas

    1. Amperage — a physical quantity equal to the ratio of the amount of charge passing through a surface over a period of time to the value of this period of time.
    2. Electrical resistance — physical quantity characterizing the property of a conductor to impede the passage of electric current and equal to the ratio of the voltage at the ends of the conductor to the strength of the current flowing through it
    3. Voltage — it is an electromotive force that pushes free electrons from one atom to another in the same direction
    Amperage I (Ampere) in the electric circuit section is directly proportional to the voltage U at the ends of the section and inversely proportional to its resistance R.