Physics

Voltage Drop Calculator

Find the voltage drop along a wire from current and resistance.

Calculated Output

Voltage drop (V) 7.5

Formula: V = I × R

Step-by-Step Breakdown

1. Values used:

2. Current = 15 A

3. Wire resistance = 0.5 Ω

5. Voltage drop = Current x Wire resistance = 15 x 0.5 = 7.5V

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The math behind it

Voltage drop = I × R (use the round-trip resistance of the conductor). Keep it under ~3% for most circuits.

15 A through 0.5 Ω → 7.5 V drop.

How do I reduce it?

Use thicker wire, shorter runs or higher voltage.