How much does it cost to run string lights?
About $0.83 a month on the typical usage below, at the U.S. average $0.1816/kWh. Set your own rate and usage and the figure updates instantly.
LED fairy lights sip only a few watts; decorative incandescent sets pull more.
Running string lights at 30W for 5 h a day costs about
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String lights are one of the cheapest things you'll ever plug in, and the reason is simple: even a whole strand is usually pulling less wattage than a single light bulb. A typical set draws around 30 watts, and LED strands can run as low as 5 watts — so leaving them on for hours barely registers next to appliances that pull hundreds or thousands of watts.
The real cost swing isn't the outlet, it's the bulb technology. Older incandescent mini-lights and decorative sets can pull several times more power than an equivalent LED strand for the same amount of sparkle, and if you're running multiple strands end-to-end around a porch, tree, or room, that difference compounds fast. Left on all evening through a season, the gap between LED and incandescent is usually the only thing that turns 'basically free' into a noticeable line item.
What drives the cost of running string lights
- Bulb type: LED strands sip a few watts total, while incandescent or decorative sets can pull 5-10x more for the same length
- How many strands you daisy-chain together — cost scales directly with total combined wattage, not per-strand price
- Hours per day they're lit, especially if left on overnight or all season rather than just evenings
How to cut it
- Switch incandescent or decorative strands to LED — same look, a fraction of the draw
- Put them on a timer or smart plug so they're not accidentally running all day or overnight
- Combine fewer, longer LED runs instead of overlapping multiple strands in the same space
- Reserve incandescent/novelty sets for short display windows (evening hours only) rather than all-day use
Data basis
- Electricity price
- U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.B, June 2026 year to date, released 2026-08-26. Retrieved 2026-09-11. Average residential revenue per kWh. A benchmark average, not a utility tariff — it excludes the fixed charges, tiers, time-of-use windows, taxes and fuel adjustments on a real bill.
- Appliance energy
- A representative running power for string lights, compiled from published manufacturer specifications and public appliance-energy guidance, and presented as a typical figure with the usual range shown above. It is not a measurement of your unit, and we do not claim a single primary source for it — the nameplate on your appliance, or an hour with a plug-in energy meter, beats any typical figure we can publish.
- Usage model
- Steady load — 30W for 5 h a day
- International prices
- rounded typical household tariffs for each market, in that market's own currency unless the row says US$ equivalent. These are planning benchmarks with no single primary source; enter the per-kWh price from your own bill for an accurate figure.
- Last reviewed
- 20 August 2026. Next scheduled review 20 February 2027.
- Corrections
- Think a figure is wrong? Tell us at corrections@watt-dollar.com and see our corrections policy.
Common questions
How much does it cost to run string lights per month?
On the assumption shown above — 30W for 5 h a day — string lights costs about $0.83 a month, or $9.94 a year, at $0.1816/kWh. That price is the U.S. average; set your own rate and usage above and the figure updates.
How is that worked out?
Power drawn while running x hours run per day. At 30W for 5 h a day that is 0.15 kWh a day, which at $0.1816/kWh costs $0.03 a day.
How can I cut the cost of running string lights?
Switch incandescent or decorative strands to LED — same look, a fraction of the draw As a worked example: running it 4 h a day instead of 5 h takes it from $9.94 to $7.95 a year, about $1.99 less.
Are LED string lights really that much cheaper than incandescent ones?
Yes. For the same length and brightness, incandescent mini-lights typically use several times more wattage than LED strands, so swapping is usually the single biggest cost lever for this category — bigger than changing how many hours you run them.
Does it cost more to run string lights all season instead of just a few hours a night?
It scales linearly with hours, so leaving lights on 12 hours a day instead of 5-6 roughly doubles the cost — but because the wattage is so low to begin with, even 'all season, all night' usually stays under a few dollars total for a typical LED display.