WeekendCalc

Christmas Lights Electricity Cost Calculator

Enter how many strands you run, their watts, how long they are on and your electricity price. You get the cost for the season, and what you save compared with old incandescent lights.

Your project

strands
W

LED strands are often 2 to 10 W. Incandescent strands are 40 to 200 W.

h
nights
$

Check your bill. The US average is around 15 to 18 cents.

W

An incandescent mini strand is about 40 W, and an incandescent C9 strand about 175 W.

Results

Cost for the season
3.06 dollars
18.0 kWh
Energy used
18.0 kWh
Per night
0.10 dollars

Compared with 40 W strands

Energy for the comparison lights
144.0 kWh
Cost for the comparison lights
24.48 dollars
You save
21.42 dollars
  • Cost = strands × watts × hours × nights ÷ 1,000 × price per kWh. Real use varies with timers and dimming. Also count inflatables, projectors and other holiday displays: they often use more than the lights.

How this calculator works

Electricity is billed in kilowatt-hours (kWh): the power in kilowatts times the hours it runs. Multiply the strands by the watts per strand to get the total watts, multiply by the hours the lights are on across the season, divide by 1,000 for kWh, and multiply by your price.

cost = strands × watts × hours per night × nights ÷ 1,000 × price per kWh

Worked example: 20 LED strands at 5 W on for 6 hours a night over 30 nights use 20 × 5 × 6 × 30 ÷ 1,000 = 18 kWh, which costs $3.06 at 17 cents. The same 20 strands in 40 W incandescent mini lights use 144 kWh and cost $24.48: a saving of $21.42.

Tips before you buy

  • A timer is the easiest saving: lights on from dusk until bedtime, instead of all night, cuts the cost and the fire risk.
  • Switching a big display to LEDs often pays for itself in a single season, and in the next ones the saving is pure profit.
  • Check the watts on the package. The number printed is more reliable than guessing from the type.
  • Large inflatables and animated displays often use more power than lights, so include them if you have them.

Tools & materials for this project

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LED C9 lights (25 ft)LED mini lights (100 count)Outdoor light timerPlug-in watt meterSmart plug (outdoor)

Frequently asked questions

How much does it cost to run Christmas lights?

LED lights typically cost a few dollars for a whole season. Incandescent lights can cost ten times as much. Enter your own strands, hours and price to see.

How many watts does a strand of Christmas lights use?

A 100-light LED mini strand uses about 4 to 5 W. An incandescent mini strand uses about 40 W, and a 25-bulb incandescent C9 strand about 175 W.

Are LED Christmas lights really cheaper to run?

Yes, by about 85 to 95%. They also last much longer, run cooler, and let you connect more strands on one outlet.

Related calculators & guides

Christmas Lights Circuit Load CalculatorHow many strands one outlet or circuit can safely run.Christmas Tree Lights CalculatorHow many lights and strands for a Christmas tree of any height.Outdoor Christmas Lights CalculatorBulbs, strands and clips to outline a roofline, windows or railing.How Many Christmas Lights Do I Need? Tree, Roofline & Circuit LoadGuide

Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.