What does an incandescent bulb cost to run?

Run the numbers on your own use

Change any of these and the figures update. The defaults are the typical case described above; your rate is the input that moves the answer most.

Why this is lower than the number you will see elsewhere

Almost every published answer to this question multiplies the rating on the label by the hours the appliance is switched on. For an incandescent bulb that gives 110 kWh a year, or $20.

Constant while lit. A filament has no thermostat, so unlike a heater or a fridge it draws its rating for every second it is on.

The arithmetic, step by step

Nothing here is hidden, so you can check it or change it. Working in the order the formula runs:

1. 60 W — what it draws while it is actually drawing. This is the rating on the plate.
2. × 100% — the share of its in-service time it is really pulling that. Constant while lit. A filament has no thermostat, so unlike a heater or a fridge it draws its rating for every second it is on.
   That gives 60 W averaged across the hours it is on.
3. × 5 hours a day × 365 days — One 60 W bulb, five hours a day.
   60 × 5 × 365 ÷ 1,000 = 110 kWh a year.
4. × 18.34¢ — the US average residential rate for June 2026.
   110 kWh × 18.34¢ = $20 a year.

Change any assumption in the calculator above and every figure on this page moves with it. The two that matter most are your rate, which varies 4× across the country, and the hours — the duty cycle is a property of the appliance, but the hours are a property of you.

How sensitive is that number?

A single figure invites more confidence than it deserves. Here is the same appliance under assumptions either side of the default, so you can see how much of the answer is the appliance and how much is the guess about how you use it.

Everything else held at the default. The spread here is the honest error bar on the headline figure.

What it costs per hour, day and month

At 18.34¢ per kWh, the US residential average for June 2026.

The thing worth knowing

About 90% of the energy leaves as heat, not light. In summer an air conditioner then removes that heat, so each bulb costs its own electricity plus the cooling to undo it.

Against LED light bulb

An LED of the same brightness for roughly a sixth of the running cost. Payback is usually a few months per bulb. In numbers: an incandescent bulb costs $20 a year on these assumptions, and led light bulb doing a comparable job costs $3.01 — a difference of $17 a year, or $171 over ten years at today’s rate.

Both at 18.34¢/kWh, each on its own standard usage assumption. Ten years is roughly the service life of either.

What it costs in your state

The appliance is the same everywhere; the rate is not. Running this incandescent bulb costs $58 a year in Hawaii and $14 in Nevada — a difference of 4×.

Cost of running one incandescent bulb for a year, by state. Residential average price, EIA June 2026.

Other lighting costs

• Grow light

  $322 a year

  One 300 W LED fixture on an 16-hour photoperiod.

• LED light bulb

  $3.01 a year

  One 60 W-equivalent bulb, five hours a day.

Questions

Source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, June 2026. U.S. Government work, public domain.

How every figure on this page is computed · Where the data comes from