Current Divider Calculator
Ik = I · (1/Rk) / Σ(1/Ri). 1 A into 100 Ω ∥ 200 Ω is 666.7 mA and 333.3 mA.
Calculator
Formula
Branch current
Ik = I · (1/Rk) / Σ(1/Ri) Parallel equivalent
Req = 1 / Σ(1/Ri) Shorted branch
R = 0 is a short and is an error Variables
| Symbol | Meaning | Unit | Typical range | Precision | Default |
|---|---|---|---|---|---|
| I | Total current | A | — | 4 sig | 1 A |
| Rk | Branch resistors | Ω | ≥ 0 mΩ R = 0 is rejected | 4 sig | 100, 200 |
| Ri | Branch i resistance | Ω | — | 4 sig | — |
| Req | Parallel equivalent | Ω | — | 4 sig | — |
| N | Branches | — | — | 4 sig | — |
| Isum | Sum of branch currents | A | — | 4 sig | — |
| Ik | Branch k current | A | — | 4 sig | — |
| I1 | Branch 1 current | A | — | 4 sig | — |
| I2 | Branch 2 current | A | — | 4 sig | — |
| I3 | Branch 3 current | A | — | 4 sig | — |
| P1 | Branch 1 power | W | — | 4 sig | — |
| P2 | Branch 2 power | W | — | 4 sig | — |
| P3 | Branch 3 power | W | — | 4 sig | — |
Worked example
1 A into 100 Ω ∥ 200 Ω
| Input | Value |
|---|---|
| I · Total current | 1 A |
| Rk · Branch resistors | 100, 200 |
| Output | Value |
|---|---|
| I1 · Branch 1 current | 666.7 mA |
| I2 · Branch 2 current | 333.3 mA |
| Req · Parallel equivalent | 66.67 Ω |
| P1 · Branch 1 power | 44.44 W |
| P2 · Branch 2 power | 22.22 W |
100 mA into 1 k / 2.2 k / 4.7 k
| Input | Value |
|---|---|
| I · Total current | 100 mA |
| Rk · Branch resistors | 1000, 2200, 4700 |
| Output | Value |
|---|---|
| I1 · Branch 1 current | 59.98 mA |
| I2 · Branch 2 current | 27.26 mA |
| I3 · Branch 3 current | 12.76 mA |
| Req · Parallel equivalent | 599.8 Ω |
How it works
Current prefers the smaller resistor. Write each branch as a conductance, normalise, and multiply by I. A typed 0 Ω is a short, not a trick to dump all current into one number — the page refuses it.
Pitfalls
- Entering 0 Ω and expecting an equal split. An ideal short has no finite branch current; this page errors.
- Forgetting that wire resistance is the real limit once a branch is a short.
- Using this AC on inductors — it is a DC resistor model.
FAQ
How does 1 A split between 100 Ω and 200 Ω?
0.667 A in 100 Ω and 0.333 A in 200 Ω.
Why is R = 0 an error?
Ik = I · (1/Rk)/Σ(1/Ri) divides by zero. Splitting current among ideal shorts has no finite answer.
Can I reverse the current sign?
Yes. Negative I just reverses every branch; power stays positive.
How many branches can I enter?
There is no hard cap on this page. Ten is a comfortable layout limit.
Related
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