What Is the LED Bulb Lifespan Calculator?
LED bulbs are sold with a rated lifespan printed in hours — commonly 15,000, 25,000, or even 50,000 hours. That number alone doesn't tell you much. This calculator converts those rated hours into something practical: how many years the bulb will actually last given how many hours per day you use it.
How to Use It
Enter the bulb's rated lifespan in hours (check the packaging) and the average number of hours you keep it switched on each day. The calculator returns the expected lifespan in years, along with months, total days of use, and the hours the bulb runs per year.
The Formula Explained
The math is simple. A year has 365 days, so a bulb used H hours per day burns H × 365 hours per year. Dividing the rated hours by that annual figure gives the lifespan in years:
$$\text{Years} = \frac{\text{Rated hours}}{\text{Hours per day} \times 365}$$
Worked Example
Suppose a bulb is rated for 25,000 hours and you use it 5 hours per day. Annual usage is \(5 \times 365 = 1{,}825\) hours. Lifespan = \(25{,}000 \div 1{,}825 \approx 13.7\) years. The same bulb left on 12 hours a day would last only about 5.7 years.
FAQ
Does the rated lifespan mean the bulb suddenly dies? Not usually. Most LED ratings (often called L70) mean the bulb still works but has dimmed to about 70% of its original brightness by that point.
What lifespan should I assume? Quality household LEDs are typically 15,000–25,000 hours; premium and commercial fixtures can reach 50,000 hours.
Why does frequent switching matter? Very frequent on/off cycling can shorten some LED drivers' life, though modern LEDs handle switching far better than fluorescent lamps.
