Landscape Lighting Calculator

Plan low-voltage (12V) landscape lighting systems. Calculate transformer size, fixture load per zone, wire run capacity, and total system wattage for residential and commercial outdoor lighting.

System Configuration

System Voltage

Transformer Size 300 W

Wire Gauge (zone runs)

Zones & Fixtures

Path / Step Lights 6

Spotlights (trees/shrubs) 4

Floodlights (walls/features) 2

Deck / In-ground Lights 4

String / Strip Zones 1

Hours per Night 6

Electricity Rate 0.13 $/kWh

Load by Zone

Transformer loading

0W300W

Est. cost per night

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Est. annual cost

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W total

System load

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fixtures

Total count

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% loaded

Transformer

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zones

Active zones

Rule of thumb: Load transformer to max 80% capacity for longevity. Keep each zone under the wire gauge limit for your run length. For 12V systems: V drop = (W × run_ft × 2) / (wire_capacity × 1000). Use daisy-chain for path lights, T-layout for spots.
LED landscape fixtures: Path/step 3–5W · Spotlights 5–15W · Floodlights 20–40W · Deck lights 1–3W · Strip zones 20–50W/run.