LED Bulb Energy Savings Calculator
LED bulbs deliver the same brightness as old incandescent or halogen bulbs at a fraction of the power, so the running-cost saving adds up fast over a year. This calculator compares an old bulb against an LED of equivalent brightness using the two wattages, the hours used per day, your electricity rate and the number of bulbs you switch. It returns the annual energy and money saved. Every value is a user-editable input so the result reflects your own bulbs and tariff.
LED savings formula
Watts saved = old wattage - LED wattage
kWh saved/year per bulb = watts saved * hours/day * 365 / 1,000
Cost saved/year per bulb = kWh saved * rate
Total = per-bulb figure * number of bulbs
The division by 1,000 converts watt-hours to kilowatt-hours. Compare bulbs of equal brightness so the saving reflects efficiency, not a dimmer light.
Getting the most from the switch
- Switch the bulbs used most hours per day first for the fastest payback.
- Match lumens, not watts, when choosing the LED replacement.
- Longer LED life adds a replacement-cost saving beyond energy.
- Use your actual tariff and usage hours for a personal figure.
LED bulb savings: frequently asked questions
How much energy does an LED bulb save?
An LED produces the same light output as an incandescent for a fraction of the wattage. The energy saved per bulb is the wattage difference times the hours used, divided by 1,000 to get kilowatt-hours. This calculator multiplies that by your electricity rate to show the running-cost saving and by the number of bulbs to show the household total.
What wattages should I compare?
Compare bulbs of equivalent brightness (lumens). A traditional 60 W incandescent is often replaced by an LED of roughly 8 to 10 W for similar light. Enter the actual wattages of the old and new bulbs; both are user-editable inputs.
What electricity rate should I use?
Use your own per-kWh price from your electricity bill. The US Energy Information Administration publishes average residential electricity prices if you want a reference. The rate is an editable input so the result reflects what you actually pay.
Do LEDs save money beyond energy?
Yes. LEDs typically last far longer than incandescent or halogen bulbs, so you replace them less often. This calculator focuses on the energy and running-cost saving; longer life adds a further replacement-cost saving on top.
Official sources
- U.S. Department of Energy: LED Lighting.
- U.S. Energy Information Administration: Electricity prices.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.