Voltage Drop Calculator (Lighting)
Quick check for DC lighting runs. Adjust cable size and length to keep end voltage in a safe range.
Target: keep ≥ 95% of supply voltage at the end
Inputs
100 ft
Run Visualization
Length: —
Vdrop: —
Vend: —(min OK: —)
Not OK
Current (A): —
Voltage Drop (V): —
Voltage at End (V): —
Result: —
FAQ
Why is the voltage drop calculated with “2 × length”?
DC circuits have a supply conductor and a return conductor. The current travels out and back, so the effective length is round-trip.
What does “OK = 95%” mean?
This calculator marks “OK” when the end voltage is at least 95% of the supply voltage.
Do I need to include driver losses?
For complex systems (multiple branches, mixed loads), a full voltage drop schedule is better.
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