Science & Engineering
Wire Voltage Drop Calculator
Estimate DC or single-phase voltage drop from current, one-way length, conductor area, and material resistivity. The calculator uses voltage drop = current × resistivity × (2 × one-way length) ÷ conductor area. It returns more than one result so you can check the main answer against a useful secondary measure. The circuit path is doubled because current travels out and back. Use electrical code tables and a qualified designer for conductor sizing, temperature correction, bundling, fault current, and legal compliance.
Educational model only. Use applicable standards, calibrated measurements, and qualified review for safety-critical work.
Calculate and compare
Use the number box for precision or the slider for fast scenario testing.
Scenario results
Estimated voltage drop
3.9331 V
Simple resistive conductor model.
Drop percentage
3.28%
Drop divided by source voltage.
Estimated load voltage
116.0669 V
Source voltage minus modeled drop.
How the calculation works
Use consistent units and retain full precision until the final display step.
Worked example
Reproduce the displayed scenario, then change one assumption at a time.
Assumptions behind the result
- • Inputs use the units shown beside each control.
- • The displayed formula is applied without hidden market or demographic data.
- • Rounding occurs only for display; calculations keep full numeric precision.
- • The circuit path is doubled because current travels out and back.
- • Use electrical code tables and a qualified designer for conductor sizing, temperature correction, bundling, fault current, and legal compliance.
Mistakes that change the answer
- • Mixing percentages with decimals or mixing incompatible units.
- • Relying on a rounded intermediate value instead of the full result.
- • Changing several assumptions at once instead of testing load current separately.