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How Much Do Christmas Lights Cost to Run?

Updated November 1, 2026 · General information, not electrical or safety advice

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The short answer: For a 6-foot tree lit 12 hours a day for 40 days, the Department of Energy says LEDs cost $0.27 and incandescents cost $10. To work out your own, multiply watts by hours, divide by 1,000, then multiply by your rate per kWh from your bill.

The sourced numbers

FactFigureSource
Cost to light a 6-foot tree, 12 hours a day for 40 days$0.27 with LEDs, $10 with incandescentsU.S. Department of Energy (article dated Dec. 16, 2015)
Energy use of LED strands70 percent less than conventional incandescent strandsU.S. Department of Energy
Energy use of ENERGY STAR certified stringsAbout 92 percent less than conventional incandescent stringsENERGY STAR
Efficiency limit for certified stringsNo more than 0.2 watts per bulbENERGY STAR
ComparisonOne 7-watt incandescent bulb uses the electricity that could power 140 LEDsENERGY STAR
HeatLEDs are more efficient and safer because they produce less heatIdaho Power

The DOE page does not say what electricity rate sits behind its dollar figures, and it is from 2015. Treat it as a size comparison, not a quote for your bill.

How to work out your own cost

This is our arithmetic. The formula is standard unit conversion, not a quoted rule.

Cost = watts ÷ 1,000 × hours × your price per kWh.

Worked example (the rate is made up to show the math)

Take one 100-bulb LED strand. If it just meets ENERGY STAR's limit of 0.2 watts per bulb, it uses at most 20 watts (100 × 0.2). Run it 12 hours a day for 40 days: 480 hours. That is 20 ÷ 1,000 × 480 = 9.6 kWh.

Your rate per kWhCost for 9.6 kWh
$0.10$0.96
$0.15$1.44
$0.20$1.92

Example rates only. Use the price on your bill. A real strand may use fewer watts than the limit, so read the box.

Doubling the hours doubles the cost, and halving them halves it. A timer that shuts the lights off at bedtime is the easiest saving. See timers and extension cords.

Watch the other loads

Want the whole comparison, with lifespan and strand limits? See LED vs incandescent. To check how many watts one outlet can take, use the calculator.

Need lights?

Pick outdoor-rated LED strings. Check the box for the wattage and for how many strands you can connect end to end.

Browse LED light stringsCount what you need first

Common questions

How much does it cost to run Christmas lights?

The Department of Energy puts it at $0.27 to light a 6-foot tree for 12 hours a day for 40 days with LEDs, versus $10 with incandescents. Your cost depends on the watts, the hours and your electric rate.

How do I calculate what my lights cost?

Multiply the total watts by the hours they run, divide by 1,000 to get kilowatt-hours, then multiply by the price per kWh on your bill. This is basic arithmetic, not a quoted rule.

Do LED Christmas lights really use less power?

Yes. The Department of Energy says LED strands use 70 percent less energy than conventional incandescent strands. ENERGY STAR says certified strings use about 92 percent less.

Related guides

Sources
  1. U.S. Department of Energy: How Do Holiday Lights Work?
  2. ENERGY STAR: Decorative Light Strings
  3. Idaho Power (electric utility): Tips for decorating safely for the holidays (Dec. 3, 2025)