LED Bulb Energy & Cost Savings Calculator
Calculate exactly how much energy and money you'll save by switching from incandescent bulbs to LEDs — plus the precise payback period for your upfront LED purchase cost.
About this calculator
Switching from incandescent to LED bulbs is one of the fastest payback home energy upgrades available. This calculator quantifies the savings precisely: it computes annual energy use for both bulb types (watts ÷ 1,000 × hours/day × 365 × number of bulbs), takes the difference to find kWh saved, multiplies by your electricity rate for dollar savings, and then divides the total upfront LED purchase cost by the annual savings to find the payback period in months. It also projects savings over the full 25,000-hour rated lifetime of a quality LED, and estimates the CO₂ emissions avoided using the EPA's US average grid emission factor of 0.386 kg per kWh.
Field explanations
- Number of bulbs
- How many bulbs of this type you are replacing. Run the calculator separately for different rooms or wattages — for example, 10 60W bulbs in living areas and 6 100W bulbs in a kitchen. Add the results together for your whole-home total.
- Current bulb wattage
- The wattage of the incandescent (or CFL) bulbs you're replacing. This is printed on the bulb itself. Common household bulbs are 40W, 60W, 75W, and 100W. The equivalency presets automatically fill in both old and new wattages for standard replacements.
- Replacement LED wattage
- The wattage of the LED you'll use as a replacement. An LED produces the same amount of light as a much higher-wattage incandescent — a 9W LED equals a 60W incandescent in brightness (800 lumens). LED packaging always lists the "equivalent to X watts incandescent" for comparison. Typical replacements use about 85% less energy than incandescent.
- Average daily run hours per bulb
- How many hours per day each bulb is on, on average. A bedroom light might run 2–3 hours/day, a kitchen 4–6 hours, and a porch light 8–12 hours. If your bulbs are on different schedules, use an average, or run separate calculations.
- Electricity rate (per kWh)
- Your local utility rate in dollars per kilowatt-hour. Find this on your electricity bill. The US average is about $0.14/kWh, but rates range from under $0.10 in some states to over $0.25 in California, Hawaii, and New England.
- Cost per LED bulb
- The purchase price of each LED replacement bulb in dollars. Basic A19 LED bulbs (60W equivalent) now cost $1–$4 each at major retailers when bought in multi-packs. Smart bulbs or specialty shapes cost more. The payback period is directly proportional to this cost — a $1 bulb pays back in a fraction of the time of a $10 bulb.