ELECTRONICS · CALCULATOR

Current divider calculator

Free current divider calculator: get branch 1 and branch 2 from current, branch 1 resistance and branch 2 resistance. With the formula shown.

Written by Chameera Sampath · Not yet reviewed by a licensed electrician. See the methodology.

US (NEC) only · NFPA 70 / NEC — locally adopted editionDefaults are US values. Verify the locally adopted NEC edition and project data.Official reference ↗

Project inputs

Measurements

Current

Branch 1 resistance

Branch 2 resistance

Updates as inputs change. Unit changes preserve the same physical values.

THE MATH BEHIND THE ANSWER

Method & assumptions

I1 = Itotal × R2 / (R1 + R2)

Two ideal parallel resistive branches.

Results do not check every aspect of an electrical installation. The calculators follow US (NEC) practice only; a regional preset changes defaults such as voltage and units, and no result certifies NEC compliance.

Sources and validation →

Worked example

Current: 20 A · Branch 1 resistance: 1,000 Ω · Branch 2 resistance: 2,000 Ω

Branch 1: 13.333 A · Branch 2: 6.667 A

This example uses the stated inputs; results for the entered values appear above.

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Estimating and invoicing tool

Ampxa is developing an estimating and invoicing application for electrical contractors. The list below receives notice when it opens.