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Calcimator

Voltage Drop Calculator

Calculate voltage drop in electrical wiring based on wire gauge, length, current, and material. Ensure your circuits meet NEC recommendations.

Inputs

V
A
ft

Results

Voltage Drop

4.76 V

Voltage Drop %3.97%
Voltage at Load115.24 V
Wire Resistance0.32 Ξ©
Power Loss71.46 W
AssessmentMarginal (3-5%)
How to Use This Calculator
  1. Enter source voltage (V) and current (A).
  2. Set wire length (one-way, ft) and select AWG gauge from the dropdown.
  3. Review voltage drop (V), voltage drop (%), and voltage at the load (V).
  4. NEC limits voltage drop to 3% for branch circuits and 5% combined for feeders + branch circuits.
  5. If voltage drop exceeds limits, increase wire gauge (lower AWG number) or reduce run length.
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Formula

Voltage Drop = Current Γ— Wire Resistance. Wire Resistance = (Resistivity Γ— 2 Γ— Length) / 1000. NEC recommends ≀3% drop for branch circuits.

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