DC cable voltage drop
Estimate cable voltage loss, resistance and the conductor area needed for a chosen drop target. Drag the graph handles to change inputs and explore the result.
Your inputs
The editable example is illustrative. Enter your own dimensions, operating data, prices, and fees. Results update as you edit.
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How it works
- ρ() = × (1 + × ( − 20)); R = ρ() × / ; ΔV = × R; Voltage drop percentage = 100 × ΔV /
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
One-way length is doubled for the return conductor. Enter resistivity at 20°C and the material’s temperature coefficient. Area is sized for voltage drop only; ampacity, connectors and electrical-code checks are separate. Example: 12 V, 5 A, 3 m one way and 2.5 mm² at 20°C give 0.21 V loss, or 1.75%.
Sources
- Blue Sea Systems — conductor voltage drop and circuit length Sources reviewed: 2026-10-22
