Electrical · Passive circuits
Resistor Network Calculator
Build series strings in parallel branches and see equivalent resistance update live — the schematic highlights whichever resistor you are editing.
Resistor values
Use Add resistor in series within a branch, or Add parallel branch for another path between the same nodes.
Parallel branches
R11
Result
Equivalent resistance
R_eq at supply nodes
R_eq
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Add resistors in series inside a branch, then add parallel branches for split current paths.
About resistor networks
Series and parallel combinations, branch reduction, and how this calculator models your schematic.
Each branch is a current path where resistors are wired in series. Multiple branches connect the same two nodes in parallel. The tool first sums each branch, then combines branch equivalents with the parallel formula.
R_branch = R₁ + R₂ + …
1/R_eq = 1/R_branch₁ + 1/R_branch₂ + …
| Layout | Formula |
|---|---|
| Two resistors in series | R_eq = R₁ + R₂ |
| Two resistors in parallel | 1/R_eq = 1/R₁ + 1/R₂ |
| N equal resistors in parallel | R_eq = R / N |
| Series string + parallel branch | 1/R_eq = 1/R_A + 1/R_B |
- Power dissipation in a series string splits by resistance only when current is equal through each element — verify with P = I²R.
- Parallel branches share voltage; current divides inversely with branch resistance.
- For node voltages and tap points, use the voltage divider calculator.
- Tolerance stacks: combine worst-case min/max per branch before parallel combination when qualifying production networks.
- Why branches instead of a flat list?
- Branch layout matches how engineers sketch split paths — one series string per parallel leg — and keeps the live schematic aligned with your inputs.
- Can I model a delta or bridge network?
- Pure series–parallel reduction works when the network can be collapsed without crossing connections. Bridge and delta–wye networks need extra transforms not covered here.
- What units are supported?
- Ω, kΩ, and MΩ. All math runs in ohms internally.