Electronics · Free Calculator
Current Divider Calculator
Find how a current splits between parallel branches. Leave R3 empty for a two resistor divider.
Two or three branchesBranch currentParallel voltageShunt design
I1 through 1 kΩ8 mA
I2 through 4 kΩ2 mA
Voltage across branches8 V
Equivalent resistance800 Ω
How this result was calculated
- Req = 1 ÷ (1/1 kΩ + 1/4 kΩ) = 800 Ω
- V = I × Req = 8 V
- In = V ÷ Rn
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Current Divider Rule
Two resistors: I1 = I × R2 ÷ (R1 + R2)
Any number: In = I × (1/Rn) ÷ Σ(1/R)
Any number: In = I × (1/Rn) ÷ Σ(1/R)
Worked example
10 mA into 1 kΩ and 4 kΩ in parallel: I1 = 10 × 4 ÷ 5 = 8 mA and I2 = 2 mA.
Key insight: current takes the easier path: the smaller resistor carries the larger share, in exact inverse proportion to resistance.
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Frequently Asked Questions
What is the current divider rule?
In parallel branches each current is inversely proportional to its resistance: I1 = I × R2 ÷ (R1 + R2) for two branches.
Where is it used?
Ammeter shunts, current sharing between parallel parts and analysing transistor bias networks.
Is the voltage the same in each branch?
Yes. Parallel branches share the same voltage.
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