LED Bulb Savings Calculator

Watts saved across all bulbs equals (old watts minus new watts) times the bulb count. That is multiplied by daily hours and 365, then divided by 1000 to get kWh saved per year. Multiplying by your rate gives the dollar saving, and the monthly figure is simply the yearly total divided by 12.

It projects your daily usage across a full calendar year, so seasonal changes are not modelled. The monthly number is the annual saving split evenly into twelve equal parts rather than a specific 30 or 31 day month.

A 9 watt LED can match the brightness of a 60 watt incandescent, so it draws about 85 percent less power. The exact percentage depends on the two wattages you enter, since the tool works from your numbers rather than assuming a fixed ratio.

No. The result is energy savings only. To estimate payback time, divide the LED purchase price by the yearly saving the tool reports, which tells you roughly how many years the swap takes to pay for itself.

The savings come out negative, meaning the replacement would cost more to run. This can occur if you compare against an already efficient bulb, and the tool will still show the negative figures rather than hiding them.

Yes, as long as every bulb shares the same wattages and run time. Set Bulb count to the number of matching fixtures. For rooms with different bulbs or schedules, run the calculator once per group and add the results.

Enter an average. If a light runs 4 hours on weekdays and 10 on weekends, an average near 6 hours per day gives a reasonable yearly estimate without needing a day by day breakdown.

Look for the price per kilowatt-hour on a recent utility bill, often shown as a supply or energy charge. Enter it in dollars, so 15 cents is 0.15. Using your real rate makes the dollar savings far more accurate than a national average.

No. The calculation runs entirely in your browser, so the wattages, hours and rate you type never leave your device and nothing is stored or uploaded.