# Round Wire Resistance Calculator

Calculates the dc Resistance of a single round wire of common conducting materials using Equation 2 below.

 INPUT DATA Conductor Material: Enter Data Aluminium Copper Gold Nickel Silver Conductor Length: mm Conductor Diameter: mm
 RESULTS Resistivity (ρ): x 10-8 Ω.m d.c. Resistance: Ω

Note: To use different values for the Resistivity, select Enter Data in the Conductor Material selection text box and then enter the required Resistivity (ρ) value in the box highlighted in amber.

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The dc resistance of a conductor is calculated using the resistivity and the cross-sectional area:-

Equation 1.

Where:

ρ is the Resistivity of the conductor in Ω.m

l is the Length in metres

A is the Cross-sectional area in metres

Round wire is normally specified by diameter and the dc resistance from the diameter is:-

Equation 2.

Where:

ρ is the Resistivity of the conductor in Ω.m

l is the Length in metres

d is the diameter of the round conductor in metres

The values for ρ are from CRC Handbook of Chemistry and Physics 1st Student Edition 1998 page F-88 and are for high purity elements at 20°C.

 Table of "bench mark" measurements made in our lab using Enamelled Copper Wire Measured Calculated Diameter Length Voltage Current Resistance Resistance (mm) (mm) (V) (A) (Ω) (Ω) 1.0 410 0.0091 1.031 0.008826 0.0087596 0.5 410 0.0359 1.031 0.03482 0.0350385 0.2 410 0.24 1.032 0.2326 0.2189908

This calculator is provided free by Chemandy Electronics in order to promote the FLEXI-BOX