Parallel Resistor Calculator
Calculate equivalent resistance for parallel networks without working through the reciprocal sum by hand.
Parallel Resistor Calculator
Enter the known values and run the calculation.
Enter the resistor values as a comma-separated list or one value per line, then run the tool.
The result reports the equivalent resistance of the full parallel network.
Overview
Calculate equivalent resistance for parallel networks without working through the reciprocal sum by hand.
Use this tool to collapse multiple parallel resistors into one equivalent resistance value.
Use it for quick network reduction, load planning, and showing how equivalent resistance falls as more parallel branches are added.
The math and how it's used
The reciprocal sum is inverted after every resistor value is normalized into ohms.
All values are treated as ideal resistors in a simple parallel network.
This is handy when several bleed paths, loads, or resistor branches need to be collapsed into one effective number before the next calculation.
If one branch is much smaller than the rest, it will dominate the answer. Real wiring resistance and tolerance stack-up still have to be handled separately if they matter.
What to watch
This assumes each resistor is ideal and that the branches are in a true parallel connection. Wiring resistance, tolerance spread, and thermal drift are not included.
If one branch is extremely small compared with the others, that one resistor will dominate the result.