Question
Why does longer wire increase voltage drop?
Longer wire adds more total resistance to the circuit path, so more voltage is lost before power reaches the load.
Daily utilities
Use OmniCalc's voltage drop calculator to estimate how much voltage is lost across a wire run based on system voltage, current, distance, conductor size, and material.
Voltage drop calculator
Enter system voltage, current, one-way distance, wire gauge, and conductor material to estimate voltage drop, delivered voltage, and percentage loss.
This version uses a simple round-trip run model and common AWG resistance values to give a fast planning estimate.
Why this result matters
A practical electrical-planning tool that opens a new internal-link cluster around wire sizing, Ohm's Law, resistors, and broader electricity intent. Use the tool above to enter a few clear inputs and get a practical answer you can use right away.
This voltage drop calculator helps users estimate wire-run losses before installation or troubleshooting. Enter voltage, current, one-way run length, conductor size, and copper or aluminum material to see the estimated voltage drop, percent loss, load voltage, and power loss quickly.
Formula and method
The calculator uses a simple round-trip conductor model. It multiplies the selected AWG resistance by the total circuit length, then uses Ohm's law to estimate voltage drop, delivered load voltage, percentage drop, and power loss.
Example
If a 120 V circuit carries 16 A across a 75-foot one-way run using 12 AWG copper, the calculator estimates the voltage drop, the percentage loss, and the approximate voltage still available at the load.
FAQ
Short answers to the questions people often ask before or after using the tool.
Question
Longer wire adds more total resistance to the circuit path, so more voltage is lost before power reaches the load.
Question
Thicker wire has lower resistance per unit length, which reduces the voltage lost across the run.
Question
It is useful for quick planning checks on branch circuits, low-voltage runs, and other installations where wire length and current can materially affect delivered voltage.
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