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# Wire resistance, length and diameter calculator

With this calculator, you can calculate the resistance of the cable, knowing the material it is made of. You can also calculate the length of the conductor and the conductor diameter or the conductor cross-section area.

## Resistance, length and diameter of wire calculator - information

The resistance of a conductor with the same cross-section to the direction of current flow is proportional to the length of the conductor, inversely proportional to the cross-section, and depends on the material, which is expressed by the relationship (sometimes called Ohm's second law):

$$R = \rho \cdot \frac {L}{S}$$ where:
R – conductor resistance,
L – conductor length,
S – conductor cross-sectional area,
ρ – conductivity (specific resistance) of a conductor, a parameter characterizing the material.

Given the diameter of a conductor, the cross-sectional area of a conductor can be calculated using the formula:

$$S = \frac{\pi \cdot d^2}{4}$$

where:
S – conductor cross-sectional area,
d – conductor diameter,

After transformations

Wire diameter:
$$d = \sqrt {S · 4 \over π}$$

Cross-sectional area:
$$S=\rho \cdot \frac{L}{R}$$

Wire length:
$$L = \frac{S \cdot R}{\rho}$$

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