Holiday Lights Electricity Cost Calculator
See what your Christmas lights add to the electric bill for the season, from the bulbs and the hours, and what the same display costs in the other kind of bulb.
Christmas lights are cheap to run or surprisingly not, and the whole difference is the bulb. This counts up your display and tells you what the season adds to the bill, what the same lights would cost in the other kind of bulb, and whether one outlet can carry it.
What kind of bulbs
Small bulbs are the classic tree-and-bush strings, each about the size of a grain of rice (the box calls them mini lights). Big bulbs are the old-fashioned thumb-sized ones along a roofline (the box says C7 or C9).
LED or old-style?
LED bulbs are cool to the touch and what most stores sell now; old-style incandescent bulbs get warm and glow a little softer. If the box says LED, it's LED.
How many bulbs in total
Add up the counts printed on the boxes. A tree is 300–600 small bulbs, bushes and railings a few hundred more, and a roofline runs 100–300 big bulbs. A typical house display is 500–1,500 bulbs.
How long they're on
Dusk to bedtime is about 6 hours; on a timer from 5 to 11 is 6; left on all night is 14.
Nights they're up
Thanksgiving to New Year's is about 40 nights; the week after Halloween through the first week of January is about 65.
Electricity rate
Your price per kilowatt-hour, from a recent bill. The 2026 U.S. average is about $0.18/kWh.
Your lights this season
about $2
600 LED small bulbs, 6 hours a night for 40 nights at $0.18/kWh
Why the bill barely moves, and what actually costs money
LED bulbs draw a few hundredths of a watt each, so even a big display runs for the season on less electricity than a single old-style roofline string. What does add up is everything that isn't a string: an inflatable's fan and lights pull 50 to 200 watts each, all night, and a projector or a music controller runs like a small appliance. Put the whole display on a timer so it's on for the six hours people see it, and if a string says LED but gets warm, it's a retrofit bulb in an old cord, which draws several times what a factory LED string does.
Cost is bulbs × watts per bulb × hours × nights × your rate. Small bulbs draw about 0.41 W old-style and 0.07 W LED; big roofline bulbs about 7 W old-style and 0.11 W LED, from the makers' figures. One outlet carries about 1,440 W of lights. Inflatables, projectors and controllers aren't counted. 2026 figures.
💡About this calculator▼
Christmas lights are either almost free to run or a real line on the January bill, and the whole difference is the bulb. An old-style bulb makes light by heating a wire, so most of the electricity leaves as warmth; an LED makes the same glow on about a tenth of the power. Six hundred small old-style bulbs draw about as much as a large TV. Six hundred LEDs draw about as much as a night light.
This counts up your display. Pick the kind of bulb, LED or old-style, enter the total bulb count from the boxes, the hours they're on each night and how many nights they're up, and your rate. You get the cost for the season and per night, the same display in the other kind of bulb, and whether one outlet can carry it.
The strings aren't usually the expensive part. A typical LED display costs a few dollars for the season. What adds up is the old-style roofline bulbs at seven watts each, lights left on all night instead of on a timer, and the inflatables and projectors that run like small appliances.
Start with the watts per bulb. Makers publish them: small old-style bulbs, the classic mini lights, draw about 0.41 watts each (a 100-count string is 41 watts), and small LEDs about 0.07 watts. Big roofline bulbs draw about 7 watts each old-style and about 0.11 watts as a factory LED string; the calculator prices big bulbs at the roofline standard, which is the larger of the two big sizes sold, so an old-style roofline errs toward the real bill.
Multiply up the season. Bulbs × watts per bulb is the display's draw; times hours a night, times nights, divided by 1,000, is the kilowatt-hours for the season; times your rate is the cost. The calculator also runs the same bulb count in the other kind of bulb, so the LED-versus-old-style decision is on the panel.
Check the outlet. A standard 15-amp household circuit should carry no more than about 1,440 watts of lights, and old-style roofline strings can only be chained two or three deep for the same reason. The calculator divides the display's watts by 1,440 to say how many outlets, on separate circuits, it needs.
Worked example. 600 small LED bulbs at 0.07 watts is 42 watts; 6 hours a night for 40 nights is 10.1 kilowatt-hours; at $0.18 that's $1.81 for the season, about 5 cents a night. The same 600 bulbs old-style draw 246 watts and cost $10.63. A roofline of 150 big old-style bulbs draws 1,050 watts and costs $45.36 for the season; in LED, 17 watts and 71 cents.
📐How it's calculated▼
Display watts = bulbs × watts per bulb. Small bulbs: 0.41 W old-style, 0.07 W LED. Big bulbs: 7 W old-style, 0.11 W LED.
Season kWh = watts × hours a night × nights ÷ 1,000. Cost = kWh × rate. Per night = cost ÷ nights.
Other kind of bulb = the same count at the other wattage.
Outlets = watts ÷ 1,440, rounded up.
Default (600 small LED, 6 h, 40 nights, $0.18): 42 W → 10.1 kWh → $1.81; old-style 246 W → $10.63, about 6 times more.
1,000 small LED bulbs: 70 W → $3.02 for the season.
150 big old-style bulbs: 1,050 W → $45.36; 73 percent of one outlet. In LED: 17 W → $0.71.
300 big old-style bulbs: 2,100 W → $90.72 and two outlets on different circuits.
2,000 small old-style bulbs left on 24 hours for 60 nights: 820 W → $212.54.
📎Sources:Christmas Designers — How Much Electricity Do LED Christmas Lights Use? (watts per bulb, display example),Christmas Lights Etc — How Many Watts and Amps Do Christmas Lights Use? (watts per strand, circuit limits),ENERGY STAR — Decorative Light Strings (92% less energy, 0.2 W per bulb cap, 10× life),U.S. Energy Information Administration — Electric Power Monthly, Table 5.6.A (average residential price per kWh)
🔍Finding your inputs▼
What kind of bulbs: Small bulbs are the classic tree-and-bush strings, each about the size of a grain of rice; the box calls them mini lights. Big bulbs are the old-fashioned thumb-sized ones along a roofline; the box says C7 or C9. If your display has both, run it twice and add the totals.
LED or old-style: LED bulbs are cool to the touch and are what most stores sell now; old-style incandescent bulbs get warm and glow a little softer. The box says which. LED bulbs screwed into an old-style cord (retrofit bulbs) draw more than a factory LED string, so treat those as somewhere between.
How many bulbs in total: Add up the counts printed on the boxes. A tree is 300 to 600 small bulbs, bushes and railings a few hundred more, a roofline 100 to 300 big bulbs; a typical house display is 500 to 1,500 bulbs.
Hours on each night: Dusk to bedtime is about 6 hours; a timer set from 5 to 11 is 6; left on all night is about 14. This is the input a timer controls, and it's worth as much as the bulb choice.
Nights they're up: Thanksgiving to New Year's is about 40 nights; the week after Halloween through the first week of January is about 65.
Electricity rate: The per-kilowatt-hour price on your bill. The 2026 U.S. average is about $0.18.
⚠️Special situations▼
The box says C7. Is that a big bulb or a small one?
Big. C7 and C9 are the two sizes of old-fashioned thumb-shaped roofline bulbs; C9 is a bit larger and is what most rooflines use, and the calculator prices big bulbs at the C9 figure of about 7 watts old-style. A C7 old-style bulb is about 5 watts, so a C7 roofline reads a little high here. Mini lights, the rice-sized ones on a tree, are the small card.
My lights say LED but the bulbs get warm.
They're probably retrofit bulbs: LED bulbs screwed into an old-style cord. Those draw about 0.4 to 0.8 watts each, several times a factory LED string's 0.11, though still far under an old-style bulb's 7. Run the calculator on the LED card and multiply the result by four to six for a rough figure, or run the old-style card and divide by ten.
Is it worth replacing working old-style strings with LED just for the electricity?
On electricity alone, rarely in one season: 600 small old-style bulbs cost about $10.63 a season versus $1.81 in LED, a saving that doesn't buy six new strings. Where it pays is the roofline, where 150 old-style bulbs cost $45 a season against 71 cents, and in the things that aren't on the bill: LED strings last up to ten times longer, stay cool against a dry tree, and chain dozens deep on one outlet. Replace the roofline and the dying strings first.
The breaker trips when everything is plugged in.
You've passed the 1,440 watts a household circuit should carry for lights, which takes about 200 old-style roofline bulbs or 3,500 old-style minis. Check the outlets row: if it says more than one, split the display across outlets on different circuits (the garage and a porch are usually separate), and never chain more old-style strings than the box allows. The same display in LED draws a few percent of that and fits on one outlet.
❓Common questions▼
How much do Christmas lights cost to run?
A typical LED display, about 600 small bulbs on for six hours a night through the holidays, costs about $1.81 for the season at the U.S. average rate, about 5 cents a night. The same display in old-style bulbs costs about $10.63. The big spend is an old-style roofline: 150 thumb-sized bulbs run about $45 for the season, and 300 run about $91 and need two outlets. In LED the same rooflines cost under $2.
How much do 1,000 LED Christmas lights cost to run?
About $3 for the season. A thousand small LED bulbs draw about 70 watts; six hours a night for 40 nights is 17 kilowatt-hours, which is $3.02 at $0.18 per kilowatt-hour, or about 8 cents a night. The same thousand bulbs old-style would draw 410 watts and cost about $17.71.
Do LED Christmas lights really use less electricity?
Yes, by a wide margin. ENERGY STAR puts certified LED light strings at about 92 percent less energy than old-style incandescent strings, with no bulb over 0.2 watts; the maker figures are 0.07 watts for a small LED against 0.41 for a small old-style bulb, and about 0.11 watts for a big LED against 7 for a big old-style one. They also last up to ten times longer and run cool, which is why a dry tree is safer with them.
How many strings of Christmas lights can I plug into one outlet?
It depends on watts, not strings. A standard household circuit should carry about 1,440 watts of lights, which is roughly 35 strings of 100 old-style minis, 200 old-style roofline bulbs, or several thousand LEDs. The makers also cap how many strings you can chain end to end: two or three for old-style roofline strings, five for old-style minis, and dozens for LEDs. Old-style displays are the ones that trip breakers.
Does a timer make a difference?
As much as the bulb choice does. Lights on from dusk to bedtime run about six hours; left on until morning they run about fourteen, more than double the cost for hours nobody sees. A plug-in timer or a smart plug set for 5 to 11 cuts an old-style roofline's season from over $100 to about $45 and keeps an LED display in the single dollars.
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