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Current Divider

I1=ItR2R1+R2I_{1} = I_{t} \frac{R_{2}}{R_{1} + R_{2}}
sig figs

Worked example: 6 A into 4 Ω ∥ 2 Ω → 2 A in the 4 Ω branch. Press Try an example to run it live, then adjust anything.

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Where Current Divider fits

Your answer feeds
Kirchhoff's Current Law (Node with Three Branches)Current Sharing Between Parallel Conductors

See also

Current Sharing Between Parallel Conductors: Both use branch current.Kirchhoff's Current Law (Node with Three Branches): Both use branch current.555 Astable Frequency: Both use resistance.LED Series Resistor: Both use resistance.Q Factor of a Series Resonant Circuit: Both use resistance.Series RL or RC Impedance: Both use resistance.
4 more relatedSeries RLC Impedance: Both use resistance.Voltage Divider: Both use resistance.RC Cutoff Frequency: Both use resistance.RL Cutoff Frequency: Both use resistance.
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Current Divider explained

ItI₁R₁R₂

Parallel branches share a voltage, so current splits inversely with resistance, and that inversion is why the opposite resistor appears on top. Six amps entering a 4 Ω branch paralleled with a 2 Ω branch sends 6 × 2/6 = 2 A through the 4 Ω path and 4 A through the 2 Ω path: the easier road takes the most traffic.

Electricians meet this as the reason parallel feeders must be identical in size, length and material: a run even slightly shorter hogs current and overheats while its twin loafs, which is exactly what the NEC's paralleling rules exist to prevent. Benchtop electronics meets it as the ammeter shunt: send 99% of the current through a milliohm resistor and measure the small remainder. Note that for more than two branches the tidy two-resistor form fails; use conductance ratios instead.

Current Divider formula

I1=ItR2R1+R2I_{1} = I_{t} \frac{R_{2}}{R_{1} + R_{2}}
Where
  • I1I_{1}= Current in branch 1 (A)
  • ItI_{t}= Total current (A)
  • R1R_{1}= Branch 1 resistance (Ω)
  • R2R_{2}= Branch 2 resistance (Ω)
Revised 16 October 2026
Cite this page

formula.expert. (2026, October 16). Current Divider Formula & Calculator. https://formula.expert/solvers/current-divider

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