BASICS · CALCULATOR

Impedance from resistance and reactance

Free impedance from resistance and reactance: get impedance and phase angle from resistance and reactance magnitude. 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

Resistance

Reactance magnitude

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

THE MATH BEHIND THE ANSWER

Method & assumptions

|Z| = √(R² + X²)

Single frequency; positive input reactance represents an inductive load.

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

Resistance: 3 Ω · Reactance magnitude: 4 Ω

Impedance: 5 Ω · Phase angle: 53.13 °

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

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