How much does an LED bulb cost to run?
An LED bulb typically draws around 9 W while running. Ratings vary widely between models, so check the label and change the figure below. An LED bulb uses about a seventh of the power of the incandescent it replaced.
- Cost per month
- 0.55
- Cost per day
- 0.02
- Cost per hour of use
- 0.00
- Energy per year
- 23.4 kWh
- Energy per day
- 0.0640 kWh
- Carbon dioxide per year
- 5.8
- Annual cost of standby alone
- 1.94
Show the working
- Power = 9
- Hours per day = 5
- Days per year in use = 365
- Electricity price = 0.28
- Standby power = 1
- Grid carbon intensity = 250
- kw = 9 / 1000 = 0.009
- daily_kwh = 0.009 * 5 = 0.045
- standby_kwh = 1 / 1000 * (24 - 5) = 0.019
- Energy per day = 0.045 + 0.019 = 0.064
- Energy per year = 0.064 * 365 = 23.36
- Cost per day = 0.064 * 0.28 = 0.017 92
- Cost per year = 23.36 * 0.28 = 6.5408
- Cost per month = 6.5408 / 12 = 0.545 067
- Cost per hour of use = 0.009 * 0.28 = 0.002 52
- Carbon dioxide per year = 23.36 * 250 / 1000 = 5.84
- Annual cost of standby alone = 0.019 * 365 * 0.28 = 1.9418
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
Scenarios & local history
Compare a saved scenario
Recent calculations
The formula
- daily energy = power in kW x hours
- annual cost = daily energy x days x price per kWh
Nameplate wattage is the maximum draw, not the average. A cycling appliance like a fridge or a freezer averages far less.
Standby draw is small per device and adds up across a house: ten devices at 2 W each is 175 kWh a year.
An LED bulb uses about a seventh of the power of the incandescent it replaced.
Running cost of an LED bulb at different tariffs
| Price per kWh | Per hour | Per year at 5 h/day |
|---|---|---|
| 0.10 | 0.0009 | 1.64 |
| 0.15 | 0.0013 | 2.46 |
| 0.20 | 0.0018 | 3.29 |
| 0.25 | 0.0022 | 4.11 |
| 0.30 | 0.0027 | 4.93 |
| 0.40 | 0.0036 | 6.57 |
Frequently asked
How many watts does an LED bulb use?
Typically around 9 W while running, though models vary. Check the rating plate.
How much electricity does it use per day?
About 0.04 kWh at 5 hours of use.