Parallel Resistor Calculator

Enter any two of the following values and press the Calculate button.

Resistor Ra:
Resistor Rb:
Parallel Resistance Rp:

A Parallel Resistor Calculator is a tool that helps you find the total (equivalent) resistance when two or more resistors are connected in parallel in an electrical circuit. In a parallel circuit, all the resistors share the same voltage across them, but the current splits among the different paths.

The formula for calculating total resistance Rt of two or more resistors in parallel is:


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Or for just two resistors:



Example Calculation:

Let's say you have two resistors:
R1=100Ω
R2=200Ω
The total resistance Rt is:


So the equivalent resistance of these two in parallel is approximately 66.67 ohms.

When more resistors are added in parallel, the total resistance decreases — it's always less than the smallest individual resistor in the group.