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Electrical Resistance Calculator

Calculate electrical resistance using voltage, current, resistivity, conductor length, cross-sectional area, power, and material properties for accurate circuit and conductor analysis.

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m
Please enter all valid positive values.
RESULTS
Resistivity
Ω·m
Formula
ρ = R × A / L

Input Parameters Specification

Resistance RMeasured conductor resistance. Unit options: Ω, kΩ and MΩ.
Length LLength of the conductor in meters.
Area ACross-sectional area of the conductor in square meters.
Resistivity ρCalculated material resistivity in ohm-meter.

Practical Operational Examples

Wire Material Check

Measure wire resistance, length and cross-section area to estimate resistivity.

Conductor Comparison

Lower resistivity means the material conducts electricity better for the same geometry.

Diagrams & Theory

This colorful original SVG shows conductor length, cross-sectional area and resistance path used in resistivity calculation.

Resistance path R A Length L ρ = R × A / L Uniform conductor sample

Formulas & Mathematical Logic

Resistivity = Area / Length × Resistance
ρ = R × A / L
Resistance is converted to ohms using the selected unit before calculation.
Length must be entered in meters and area must be entered in square meters.

Step-by-Step Example

Example: Resistance = 2 Ω, Length = 5 m, Area = 0.000001 m².
ρ = R × A / L
ρ = 2 × 0.000001 / 5
ρ = 0.0000004 Ω·m

How to Use This Calculator

Enter measured resistance.
Select resistance unit: Ω, kΩ or MΩ.
Enter conductor length in meters.
Enter cross-sectional area in square meters.
Click Calculate to get resistivity.

About This Calculator

Calculate material resistivity from conductor geometry.

This Resistivity Calculator estimates electrical resistivity using resistance, length and cross-sectional area.

Electrical resistivity describes how strongly a material opposes current flow. It is different from resistance because resistance depends on the physical size of the conductor, while resistivity is a material property. A long thin wire has more resistance than a short thick wire, even if both are made from the same material. By using length and cross-sectional area, this calculator converts a measured resistance into resistivity.

ResistanceMeasured opposition to current flow.
LengthLonger conductors usually have higher resistance.
AreaLarger cross-section usually lowers resistance.
ResistivityMaterial-level property shown in Ω·m.
Tip: For accurate resistivity testing, use a stable temperature and reliable four-wire resistance measurement when values are very low.

Frequently Asked Questions

What is resistivity?

Resistivity is a material property that tells how strongly the material resists electric current.

What is the formula for resistivity?

The formula is ρ = R × A / L, where R is resistance, A is area and L is length.

What unit is resistivity measured in?

Resistivity is commonly measured in ohm-meter, written as Ω·m.

Is resistivity the same as resistance?

No. Resistance depends on size and shape, while resistivity describes the material itself.

Why does area matter?

A larger cross-sectional area gives current more path to flow, reducing resistance for the same material.

Can I use this for copper wire?

Yes, if you know resistance, length and cross-sectional area of the copper conductor.

Does temperature affect resistivity?

Yes. Many materials change resistivity with temperature.

Related Calculators

Ohm’s Law CalculatorCalculate voltage, current, resistance and power.
Wire Resistance CalculatorEstimate conductor resistance from material and length.
PCB Trace Resistance CalculatorUseful for PCB conductor resistance checks.
Conductivity CalculatorConvert between resistivity and conductivity.

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About this tool

Electrical Resistance Calculator is a free online calculator tool. Use it to get instant, accurate results for your electronics calculations.