Parallel Resistance Calculator
Electrical & HVACCalculate equivalent resistance for parallel and series circuits with two, three, four, or more resistors. This calculator instantly finds total resistance using standard electrical formulas.
How to Use Parallel Resistance Calculator
Frequently Asked Questions
What is parallel resistance?
Resistors are said to be in parallel when they are connected across the same two nodes, such that multiple exists current paths. It is analogus to water flowing in a pipe and given a branch. The equivalent resistance is always lower than the smallest individual resistor.
How do I calculate 3 resistors in parallel?
To calculate three resistors in parallel, add the inverse of each resistance (1/R1 + 1/R2 + 1/R3), then take the reciprocal of the result. This calculator performs that calculation automatically.
Can I calculate 4 or more resistors in parallel with this tool?
Yes. The calculator supports four resistors in parallel and any additional number of resistors, using the general inverse-sum formula for accurate results.
What formula is used for parallel resistance?
Parallel resistance is calculated using the inverse-sum formula: 1/Req = 1/R1 + 1/R2 + … . The equivalent resistance is the reciprocal of this sum.
Does this calculator also work for series resistors?
Yes. In series mode, the calculator adds all resistor values together to find the total resistance.
Who should use a parallel resistor calculator?
This tool is designed for electricians, HVAC technicians, engineers, students, and anyone who needs to calculate equivalent resistance in real electrical circuits.