Parallel resistor calculator

Calculator and formulas for calculating 2 resistors in parallel


This function calculates the total or parallel resistance of a parallel circuit using two resistors.

For the calculation, select whether the total or parallel resistance R2 should be calculated. Then enter the values and click on the Calculate button.


Resistance calculator

 What should be calculated?
 Input
Resistor R1
Total resistance
Resistor R2
Decimal places
 Result
Total resistance
Resistance R2

Formulas for resistance parallel circuit


In order to calculate the total resistance of several resistors connected in parallel, their conductance values are added. The conductance is the reciprocal of the resistance. The formula for three resistors connected in parallel is

\(\displaystyle \frac{1}{R_{ges}}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}\)

When calculating two parallel resistances, the total resistance can be calculated using the following formula.

\(\displaystyle R_{ges}=\frac{R_1· R_2}{R_1 + R_2}\)

The parallel resistance R2 is calculated using the following formula.

\(\displaystyle R_2=\frac{R_1· R_{ges}}{R_1 - R_{ges}}\)


Circuits with resistors

Total resistance of a resistor in parallel
Parallel- total resistance of 2 resistors
Series resistance for a voltmeter
Parallel resistance for an ampere meter
Voltage divider
Loaded voltage divider
Pi Attenuator
T Attenuator


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