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Outdoor Lighting Input Power and Energy Calculator

Calculate fixture input power and runtime energy, or use matched fixture lumens and luminous efficacy to calculate input watts.

Use this result well

Inputs that matter
Whole fixtures, Input watts per fixture, Operating hours per day, Operating days, and 4 more
Output to expect
Outdoor lighting power and energy, Lumens and matched efficacy
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

Outdoor lighting power and energy

Use actual whole-system input watts per fixture, including its driver on a consistent basis. Enter the number of fixtures and your chosen operating schedule and tariff. This estimates energy cost only; it does not calculate brightness, transformer VA, wiring ampacity or circuit compliance.

Input watts = fixtures × watts per fixture; energy kWh = watts × hours per day × days ÷ 1000; variable energy cost = kWh × tariff.

Lumens and matched efficacy

Calculate input power from a manufacturer’s stated light output and efficacy measured on the same basis. Do not combine bare-LED efficacy with complete-fixture lumens. A power result does not establish useful illuminance at a path or work surface.

Estimated watts = fixture lumens ÷ matching lumens per input watt × fixture count.

Updated: September 2026

Example Scenarios

The built-in example uses fictional planning records. Replace these with your own verified details.

→ 48 W input

The built-in example uses fictional planning records. Replace these with your own verified details.

→ 48 W

FAQ

No. Use manufacturer input data on a consistent basis. Transformer VA, voltage drop, ampacity, listing and installation requirements need their own circuit review.

Use your own records on the units and period shown. Verify current requirements, enter explicit zeros for absent amounts where requested and retain dated sources.

Choose Save planning case for local history. Copy MD includes current inputs, notes and interpretation; Download CSV exports the result breakdown. Keep a portable copy separately.

About Outdoor Lighting Input Power and Energy Calculator

Use actual whole-system input watts per fixture, including its driver on a consistent basis. Enter the number of fixtures and your chosen operating schedule and tariff. This estimates energy cost only; it does not calculate brightness, transformer VA, wiring ampacity or circuit compliance. Calculate input power from a manufacturer’s stated light output and efficacy measured on the same basis. Do not combine bare-LED efficacy with complete-fixture lumens. A power result does not establish useful illuminance at a path or work surface.