How to Use This Calculator
- Select the wire gauge.
- Enter the run distance (feet).
- Enter the total load in VA (use the VA value).
- Choose your minimum acceptable end voltage (fixture/LED dependent).
- Click Calculate (if results don’t appear automatically).
Landscape Lighting Voltage Drop Calculator
| Tap Voltage | Voltage At End | Max Distance ≥ Min Voltage | Add’l Load Allowed (to Min V) |
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What Is Voltage Drop?
Voltage drop is the reduction in voltage that occurs as current moves through a cable. Because every conductor has some resistance, a portion of the supplied voltage is lost along the length of the run.
Practically speaking, it’s the difference between the voltage measured at the transformer (start of the run) and the voltage at the final fixture (end of the run). When the drop is excessive, fixtures farther from the transformer can appear dimmer than those closer to it.
Assumptions & Guidance
This tool assumes a typical low-voltage lighting setup with 120 VAC input to the transformer and 12 VAC output. It is intended as a planning aid to help you start your layout.
Always verify actual voltage at each fixture with a calibrated voltmeter before backfilling or finalizing your installation.
Disclaimer: Results are estimates only. Use at your own discretion. We cannot accept responsibility for any outcomes resulting from the use of this information.