Circuit Analysis calculator
Parallel Circuit Calculator
Use this resistive parallel branch calculator when each entered branch is connected across the same source voltage. It models up to five resistive branches, applies the standard 1/R_eq = Sigma(1/R_i) relationship, and then calculates branch current, total current, conductance, and resistive power when a source voltage is part of the problem. For a broader DC or RLC operating-point check, use the Circuit Analysis Calculator.
Updated July 10, 2026
Enter source voltage and each resistive parallel branch before using the result. This tool solves equivalent resistance, branch current, total current, conductance, and branch power for the exact branch set you enter.
Parallel method: add branch conductance first, invert to equivalent resistance, then calculate branch and total current from the entered source voltage.
Enter source voltage and 2 to 5 branch resistances below to solve equivalent resistance, branch current, total current, and resistive power
Calculator Inputs
Calculation Results
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Field kit
Bench kit for parallel checks
Build a small low-voltage example from the calculated branch values, then verify it with basic bench tools.
Compare multimetersFor branch measurementsOpens in a new tabFind resistor kitsFor parallel examplesOpens in a new tabAdd jumper wiresFor temporary layoutsOpens in a new tab
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Calculation history
Example Calculations
More examples. Open to review 1 additional calculation example.
How to Use
How to use the parallel circuit calculator
- Select the calculation mode: basic analysis, power analysis, circuit design, or current-divider review.
- Enter at least two branch resistances. Add branches 3 through 5 only when needed.
- For basic, power, or current divider modes, enter the source voltage. Every branch is treated as being connected across that same voltage.
- For design mode, enter the target equivalent resistance. The calculator will show the extra resistor needed in parallel when the target is lower than the current equivalent resistance.
What each mode returns
| Mode | Primary outputs | Best use |
|---|---|---|
| Basic analysis | Equivalent resistance, total current, branch currents, branch power, total power, and current verification | General resistor-network checks |
| Power analysis | Equivalent resistance plus branch and total wattage | Resistive load and heat checks |
| Circuit design | Equivalent resistance, conductance, and the additional resistor needed for a target R_eq | Adding a new branch to hit a resistance target |
| Current divider | Equivalent resistance, branch current, total current, and each branch percentage of total current | Current-sharing comparisons between resistive branches |
Important scope notes
- This calculator treats every branch as a resistive branch. It does not solve complex impedance, phase angle, or mixed R-L-C networks.
- It does not replace conductor sizing, breaker sizing, or dwelling-load calculations for actual building wiring.
- If you only need equivalent resistance, the Parallel Resistor Calculator is the faster screen. For series-only work, use the Series Circuit Calculator. For one-source DC or RLC operating-point checks, use the Circuit Analysis Calculator. For V-I-R checks on a single branch, use the Ohm's Law Calculator.
After entering your branch values, use the generated result to review equivalent resistance, branch current, and total current for that specific branch set.
Common Applications
More applications. Open to review 3 additional use cases.
Frequently Asked Questions
Why is the voltage the same across every branch in a parallel circuit?
Because every branch is connected across the same two electrical nodes. In an ideal parallel network, that means each branch sees the same applied voltage, while current changes from branch to branch according to resistance.
Why is equivalent resistance always lower than the smallest branch resistance?
Adding a parallel branch adds another current path. That increases total conductance, so the equivalent resistance drops below the smallest individual branch resistance.
What is the difference between this page and a current-divider formula?
This page includes the current-divider result, but it does not stop there. It also solves equivalent resistance, total current, conductance, and resistive power for the same branch set.
Can I use this calculator for actual household circuit capacity or breaker sizing?
Not by itself. It is a resistor-network solver. For real building-circuit planning, use conductor, breaker, or load calculators that include the code and installation assumptions that this page intentionally does not model.
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