Resistor Combinations

Build series / parallel groups and get instant equivalent resistance, show-work steps, and a clean share link.

How to Use

  1. Choose a topology: Series, Parallel, or Mixed Groups.
  2. Enter resistor values and select units (Ω / kΩ / MΩ).
  3. For Mixed Groups: create groups, set each group as series/parallel, then combine groups.
  4. Open “Show Work” to see each step (group totals and final equivalent).
Network Lab View
Visual feedback: topology, group totals, and final equivalent resistance.
Mode
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Inputs
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Req
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Hint
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Status: —
Topology Preview Not a simulator — just a clean visual summary of the network you enter. R1 R2 R3 Series R1 R2 Parallel Mixed Groups: compute each group total, then combine totals. Group A Group B Tip: 0Ω in parallel implies an ideal short (Req → 0Ω). Use “Show Work” to see why.
Inputs & Settings
Enter resistor values. Switch topology at any time.
Mixed Groups lets you compute Group A + Group B totals, then combine totals.
Inputs are interpreted in this unit. Work output is shown in base Ω.
Resistors
Add/remove rows. Blank rows are ignored.
Show Work (step-by-step)
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Work is shown in base units (Ω) for clarity. Inputs can be Ω / kΩ / MΩ.

Formulas

Series: Req = R1 + R2 + … + Rn

Parallel: 1/Req = 1/R1 + 1/R2 + … + 1/Rn

Mixed Groups: compute each group’s equivalent first, then combine group totals (series or parallel).

FAQ

Why is parallel always smaller than the smallest resistor?

Parallel adds conductance: each branch provides another path, so total resistance decreases.

What does 0Ω do in series vs parallel?

In series it adds nothing (ideal short). In parallel it dominates: any 0Ω branch makes Req → 0Ω.

Can I model “two resistors in parallel then in series with another”?

Yes — use Mixed Groups. Put the two resistors in a group set to parallel, compute that group, then combine with the other group in series.

Tool Info

Last updated:

Updates may include UI improvements, more group slots, and export enhancements.