Low-Voltage Lighting Calculator

Calculate voltage drop for LED strips and landscape lighting

Project Details
Enter your measurements and requirements
Results
Calculated estimates for your project
Voltage Drop1.32V (11.0%)
Voltage at Load10.68V
Current Draw8.33 Amps
Wire Resistance0.159 Ohms
StatusPoor - Increase wire size
RecommendationUse larger wire gauge

Additional Information

About This Voltage Drop Calculator

Our voltage drop calculator helps you size wiring for low-voltage lighting systems, including LED strips, landscape lighting, and 12/24V systems. Excessive voltage drop causes dim lights at the end of runs and can damage LEDs by causing them to draw more current.

Low-voltage systems are particularly sensitive to voltage drop because the percentage lost is much higher at 12V than at 120V. A 1-volt drop represents 8% loss at 12V but less than 1% at 120V. Proper wire sizing ensures consistent brightness and extends LED lifespan.

This calculator is essential for landscape lighting installers, LED strip users, and anyone asking "what wire size for 12V LED lights?" or "why are my landscape lights dim?" Keep voltage drop under 5% for best results, under 10% maximum.

How to Use This Calculator

Follow these steps to calculate voltage drop:

  1. Enter your system voltage (12V or 24V typical)
  2. Calculate total wattage of all lights on the circuit
  3. Measure wire run length from transformer to furthest light
  4. Select your wire gauge (AWG)
  5. Review voltage drop percentage and upgrade wire if needed
Frequently Asked Questions

What is acceptable voltage drop for LED lighting?

Keep voltage drop under 5% for optimal LED performance and longevity. Up to 10% is acceptable but may cause visible dimming on some fixtures. Over 10% causes noticeable dimming and can damage LEDs. Higher-quality LEDs tolerate voltage variation better than cheap ones.

Should I use 12V or 24V landscape lighting?

24V systems have half the voltage drop of 12V systems for the same wire and distance. Use 24V for long runs over 50 feet or high-wattage installations. 12V is standard for shorter runs and simpler systems. More fixtures are available in 12V, but 24V is growing in popularity.

What wire gauge for landscape lighting?

Use 12 AWG for runs over 50 feet or over 100W total load. 14 AWG works for moderate runs of 25-50 feet. 16 AWG is suitable only for short runs under 25 feet with light loads. When in doubt, use larger wire - the cost difference is minimal compared to digging up undersized wire.

Why do my LED strips get dimmer at the end?

LED strips draw power from one end, causing voltage drop along the strip. Long runs or high-density strips show noticeable dimming. Solutions include: power injection at both ends, parallel runs, using 24V strips, or breaking into shorter segments with separate power feeds.

How do I wire landscape lights to minimize voltage drop?

Use a hub or "T" method with the main cable running to the center of the system. Run separate home-run wires from the transformer to different areas. Balance loads across multiple transformer taps. Use larger wire for the main run and branch to fixtures with smaller wire.

Does wire type affect voltage drop?

Copper wire has lower resistance than aluminum. Use copper for landscape lighting. Direct burial cable is required for underground runs. Multi-strand wire is easier to work with but has slightly higher resistance than solid wire. Use cable rated for outdoor and direct burial use.

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