Resistor Calculator

The following are tools to calculate the total resistance of a group of resistors in parallel or in series. A complex circuit can typically be divided into simpler circuits in parallel and series to determine the total resistance (by summing the resistance of each portion). A calculator for estimating the resistance of a conductor based on size and conductivity is also included.

Resistors in parallel

Provide all of the resistance values in parallel, separated by a comma "," and click the "Calculate" button to determine total resistance.


Resistors in series

Provide all of the resistance values in series separate d by a comma "," and click the "Calculate" button to determine total resistance.


Resistance of a Conductor

Use the following to calculate the resistance of a conductor. This calculator assumes the conductor is round.

Length:
Diameter:
Conductivity: S/m       Or Select Material


RelatedOhms Law Calculator


Resistors are circuit elements that impart electrical resistance. While circuits can be highly complicated, and there are many different ways in which resistors can be arranged in a circuit, resistors in complex circuits can typically be broken down and classified as being connected in series or in parallel.

Resistor in parallel:

The total resistance of resistors in parallel is equal to the reciprocal of the sum of the reciprocals of each individual resistor. Refer to the equation below for clarification:

Rtotal
1
1
R1
 + 
1
R2
 + 
1
R3
 + ... + 
1
Rn

Resistor in series:

The total resistance of resistors in parallel is simply the sum of the resistances of each resistor. Refer to the equation below for clarification:

Rtotal = R1 + R2 + R3 ... + Rn

Resistance of a conductor:

R = 
L
A × C

Where:
    L is the length of the conductor
    A is the cross-sectional area of the conductor
    C is the conductivity of the material