Wire voltage drop

How the calculation works

Estimate wire resistance, voltage drop and power loss in a DC circuit. The tool converts the form units and presents the result using readable engineering notation.

R = ρ × 2L / A; ΔV = I × R

Example

For 5 m of 1 mm² copper wire at 2 A, the drop is about 0.17 V.

How to interpret the result

• Length is the one-way distance; the calculation includes the return conductor.
• Metal resistance rises with temperature.
• Connectors, fuses and PCB traces add extra drop beyond the wire result.

Limitations and safe use

The result uses a simplified model. Check tolerance, temperature, absolute ratings and the component datasheet.