About the LED Savings Calculator
This LED savings calculator shows what you gain by swapping old light bulbs for LEDs. Enter how many bulbs you are replacing, the wattage of the old and new bulbs, how long they are on each day and your electricity rate, and it calculates the kilowatt-hours and money saved each year, how quickly the new bulbs pay for themselves and the savings over the LEDs’ life.
It also counts the replacement bulbs you no longer need to buy: a traditional incandescent lasts about 1,000 hours, halogens 2,000–3,000 and CFLs around 8,000–10,000, while a quality LED is typically rated 15,000–25,000 hours. That matters most in fixtures that are on for many hours a day, such as porches, kitchens and offices.
LEDs are compared by light output (lumens), not watts: a 60 W incandescent (about 800 lumens) is usually replaced by an 8–10 W LED, a 100 W bulb (about 1,600 lumens) by a 14–17 W LED. The default electricity rate of $0.17/kWh is close to the 2025 US residential average from the EIA (17.3¢). The CO₂ figure uses the US-average grid emission rate from EPA eGRID2023, about 0.35 kg per kWh.
With the default inputs, the total savings per year is $218.34. Change any value above to recalculate instantly.
How to use the led savings calculator
- 1Count the bulbs you plan to replace and enter their current wattage.
- 2Enter the wattage of the LED replacement with similar lumens.
- 3Estimate the average hours per day the lights are on.
- 4Enter your electricity rate and bulb prices and lifespans.
- 5Review yearly savings, payback time and lifetime savings.
Formula and method
Energy saved is the wattage difference times the hours the lights are on in a year, converted to kWh and multiplied by your rate. Avoided bulb purchases are the old bulbs you would otherwise burn through each year (hours per year ÷ old lifespan × price); in the long run the LEDs themselves also need replacing, which is subtracted at their own lifespan and price to give the total yearly saving.
Payback compares the upfront cost of the LEDs with what you stop spending on electricity and old bulbs, because the first set of LEDs does not need replacing during its life. Net savings over LED life multiply that yearly benefit by the LED lifespan in years at your usage and subtract the upfront cost.
- W_old
- Wattage of the bulb being replaced
- W_LED
- Wattage of the replacement LED
- hours/day
- Average hours each bulb is on per day
Worked examples
20 × 60 W incandescent to 9 W LED
Each bulb saves 51 W for 1,095 hours a year, so 20 bulbs save 1,116.9 kWh or $189.87 at $0.17/kWh. You also avoid buying about 22 incandescents a year ($32.85), minus $4.38 a year of amortized LED replacements, for $218 in total yearly savings. The $60 of LEDs pays back in about 3.2 months, the 15,000-hour LEDs last 13.7 years at this usage for $2,991 net savings, and about 391 kg of CO₂ is avoided each year at 0.35 kg/kWh.
Office with 50 halogen downlights on 10 hours a day
Fifty lights each saving 44 W for 3,650 hours a year save 8,030 kWh, or $1,445 at $0.18/kWh. Halogens rated for 2,000 hours would need replacing about 91 times a year ($274); the LEDs add only $36.50 a year of amortized replacements, for about $1,683 saved each year. The $250 of LEDs pay back in about 1.7 months.
Replacing 10 CFLs with LEDs
CFLs are already efficient, so replacing ten 14 W CFLs with 9 W LEDs saves just 73 kWh ($12.41 at $0.17/kWh) a year. Including avoided CFL purchases ($4.56) minus amortized LED replacements ($2.92) the saving is about $14 a year, and the $30 of LEDs take about 21 months to pay back.
Frequently asked questions
How much money do LED bulbs really save?+
Replacing a 60 W incandescent with a 9 W LED used 3 hours a day saves about 56 kWh a year per bulb — roughly $9.50 at $0.17/kWh. Across 20–40 bulbs in a home that is about $190–$380 a year, plus fewer replacement bulbs.
What wattage LED replaces a 60 W bulb?+
Match light output in lumens. A 60 W incandescent gives about 800 lumens, which a typical 8–10 W LED matches. A 75 W bulb (about 1,100 lumens) needs an 11–13 W LED and a 100 W bulb (about 1,600 lumens) a 14–17 W LED.
How long do LED bulbs last?+
Quality LEDs are usually rated 15,000–25,000 hours, often more for commercial fixtures. At 3 hours a day, 15,000 hours is about 13.7 years. Heat, enclosed fixtures and frequent dimming can shorten real-world life.
Is it worth replacing CFLs with LEDs?+
Savings are much smaller because CFLs already use about 70–75% less energy than incandescents. Many people replace CFLs as they burn out rather than all at once; LEDs still offer instant full brightness, better dimming and no mercury.
Can I still buy incandescent or halogen bulbs in the US?+
Mostly not for everyday lighting. A 2022 Department of Energy rule bans the sale of general-service bulbs that deliver less than 45 lumens per watt, and it has been fully enforced against retailers since mid-2023. Standard incandescent and halogen bulbs cannot meet that standard. Specialty bulbs, such as appliance lamps and some decorative lamps, are exempt, so LEDs are now the normal replacement.
Do LEDs save money if lights are rarely used?+
Yes, but slowly. The payback time grows as usage falls: a closet light used 15 minutes a day may take years to pay back. Prioritize fixtures that are on for many hours each day, such as kitchens, living rooms and outdoor lights.
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