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Wire Resistance Calculator.

Calculate DC resistance from resistivity, length, and cross-sectional area.

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Set your values

Results update as you type.

02 / ANSWER

Resistivity

Length

Cross-sectional area

Resistance

0.000000Ω

Results update automatically as you type.

Use Cases

Electrical Engineering Design

Determine the resistance of a wire for circuit design, voltage drop calculations, or power loss estimation.

Example: Calculate the resistance of a 100 m copper wire with a cross-sectional area of 1 mm² (1e-6 m²).

Physics Education

Verify theoretical resistance values in lab experiments or homework problems involving resistivity.

Example: Find the resistance of a nichrome wire with resistivity 1.1e-6 Ω·m, length 2 m, and area 0.5 mm².

Frequently Asked Questions

How do I use the Wire Resistance Calculator?: Enter the resistivity of the material (in Ω·m), the length of the wire (in meters), and the cross-sectional area (in square meters). The calculator will compute the DC resistance using the formula R = ρ * L / A.
What units are used in this calculator?: Resistivity is in ohm-meters (Ω·m), length is in meters (m), and cross-sectional area is in square meters (m²). The result is in ohms (Ω).
Can I use this calculator for AC wires?: This calculator is designed for DC resistance. For AC, factors like skin effect and inductance may affect the effective resistance, so it's not recommended for high-frequency AC applications.

Tips & Common Mistakes

Tips

Ensure all inputs are in the correct SI units: resistivity in Ω·m, length in m, area in m². Convert if necessary.
For a circular wire, area = π * (diameter/2)². If you have diameter, compute area first.
Use the resistivity value specific to the material and temperature, as resistivity changes with temperature.
Double-check your area conversion: 1 mm² = 1e-6 m², 1 cm² = 1e-4 m².

Common Mistakes to Avoid

Forgetting to convert cross-sectional area to square meters (e.g., using mm² directly).
Using diameter instead of radius in the area calculation for circular wires.
Confusing resistivity with resistance; resistivity is a material property, resistance depends on geometry.

Last updated: August 13, 2026

Use Cases

Electrical Engineering Design

Determine the resistance of a wire for circuit design, voltage drop calculations, or power loss estimation.

Example: Calculate the resistance of a 100 m copper wire with a cross-sectional area of 1 mm² (1e-6 m²).

Physics Education

Verify theoretical resistance values in lab experiments or homework problems involving resistivity.

Example: Find the resistance of a nichrome wire with resistivity 1.1e-6 Ω·m, length 2 m, and area 0.5 mm².

Frequently Asked Questions

How do I use the Wire Resistance Calculator?

Enter the resistivity of the material (in Ω·m), the length of the wire (in meters), and the cross-sectional area (in square meters). The calculator will compute the DC resistance using the formula R = ρ * L / A.

What units are used in this calculator?

Resistivity is in ohm-meters (Ω·m), length is in meters (m), and cross-sectional area is in square meters (m²). The result is in ohms (Ω).

Can I use this calculator for AC wires?

This calculator is designed for DC resistance. For AC, factors like skin effect and inductance may affect the effective resistance, so it's not recommended for high-frequency AC applications.

Tips & Common Mistakes

Tips

Ensure all inputs are in the correct SI units: resistivity in Ω·m, length in m, area in m². Convert if necessary.
For a circular wire, area = π * (diameter/2)². If you have diameter, compute area first.
Use the resistivity value specific to the material and temperature, as resistivity changes with temperature.
Double-check your area conversion: 1 mm² = 1e-6 m², 1 cm² = 1e-4 m².

Common Mistakes to Avoid

Forgetting to convert cross-sectional area to square meters (e.g., using mm² directly).
Using diameter instead of radius in the area calculation for circular wires.
Confusing resistivity with resistance; resistivity is a material property, resistance depends on geometry.

Use Cases

Electrical Engineering Design

Determine the resistance of a wire for circuit design, voltage drop calculations, or power loss estimation.

Example: Calculate the resistance of a 100 m copper wire with a cross-sectional area of 1 mm² (1e-6 m²).

Physics Education

Verify theoretical resistance values in lab experiments or homework problems involving resistivity.

Example: Find the resistance of a nichrome wire with resistivity 1.1e-6 Ω·m, length 2 m, and area 0.5 mm².

Frequently Asked Questions

How do I use the Wire Resistance Calculator?

What units are used in this calculator?

Resistivity is in ohm-meters (Ω·m), length is in meters (m), and cross-sectional area is in square meters (m²). The result is in ohms (Ω).

Can I use this calculator for AC wires?

This calculator is designed for DC resistance. For AC, factors like skin effect and inductance may affect the effective resistance, so it's not recommended for high-frequency AC applications.

Tips & Common Mistakes

Tips

Ensure all inputs are in the correct SI units: resistivity in Ω·m, length in m, area in m². Convert if necessary.
For a circular wire, area = π * (diameter/2)². If you have diameter, compute area first.
Use the resistivity value specific to the material and temperature, as resistivity changes with temperature.
Double-check your area conversion: 1 mm² = 1e-6 m², 1 cm² = 1e-4 m².

Common Mistakes to Avoid

Forgetting to convert cross-sectional area to square meters (e.g., using mm² directly).
Using diameter instead of radius in the area calculation for circular wires.
Confusing resistivity with resistance; resistivity is a material property, resistance depends on geometry.