Calculate equivalent resistance for two or more resistors in parallel, with total conductance and optional branch current and power breakdown from a shared supply voltage.
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Basic circuits
A parallel resistor calculator shows how multiple branches combine into one equivalent resistance that is always lower than the smallest participating resistor. This version also exposes total conductance and, when a supply voltage is entered, branch current and power so the network can be checked as a practical circuit rather than as a bare formula exercise.
This page accepts two or more resistor values, converts mixed input units into ohms, and solves the equivalent resistance by summing branch conductance.
An optional supply voltage adds branch-by-branch current and power so you can see how the load splits across the network instead of stopping at the equivalent resistance alone.
In a parallel network each branch provides another path for current, so the total conductance increases as more valid branches are added. Equivalent resistance is then the reciprocal of that total conductance.
That is why the equivalent resistance of a true parallel network always comes out lower than the smallest branch resistance.
Gtotal = 1/R1 + 1/R2 + ... + 1/Rn
Each resistor contributes conductance to the shared network.
Req = 1 / Gtotal
Equivalent resistance is the reciprocal of the combined conductance.
Once a supply voltage is entered, each resistor branch uses that same branch voltage to determine its current and power. Lower-resistance branches therefore draw more current and dissipate more power.
The branch table is useful when you need to spot a hot branch, verify current sharing, or confirm whether one resistor dominates the load.
Ibranch = V / Rbranch
Branch current follows directly from the shared branch voltage and the resistor value.
Pbranch = V × Ibranch = V² / Rbranch
Branch power grows as resistance falls when the branch voltage is fixed.
This calculator assumes ideal resistors in a simple DC-style parallel network. It does not model temperature rise, tolerance stacking, inductance, wiring resistance, or any reactive behaviour.
Use it as a planning and educational reference. If the network includes capacitors, inductors, time-varying sources, or thermal constraints, switch to the calculator that models those effects explicitly.
Frequently asked questions
Because adding a parallel branch creates another current path, which increases total conductance. The reciprocal of that larger conductance is a smaller equivalent resistance.
Yes in the ideal model. Parallel branches connect across the same two nodes, so each branch sees the same node-to-node voltage.
Yes. This calculator normalizes the entered branch values into ohms before it sums conductance and solves the equivalent resistance.
Related
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