Lumen to Watt Converter
ENERGY STARIES Handbook
ENERGY STARIES Handbook
Light Output Conversion
Enter your light output value and select a light source type to calculate equivalent wattages.
Frequently Asked Questions
Common questions about this calculator
Watts = Lumens ÷ Luminous Efficacy (lm/W). Example: 1600 lumens ÷ 100 lm/W = 16 W. The calculator lets you choose or enter the efficacy based on lamp type.
Different technologies convert electrical power to light with different efficiencies. Typical ranges: incandescent 10-17 lm/W, halogen 15-25 lm/W, CFL 50-70 lm/W, LED 80-120 lm/W, premium LED 130-180 lm/W.
Most modern LEDs range from 80 to 120 lm/W. High-performance fixtures can exceed 150 lm/W. Check the product datasheet for the most accurate conversion.
Yes. Lumens = Watts × Luminous Efficacy. If a 12 W LED runs at 100 lm/W, it produces about 1200 lumens.
Yes. Cool white LEDs often have slightly higher lumens per watt than warm white LEDs due to phosphor efficiency. Expect a 5-15% difference between warm and cool variants.
No. It depends on driver efficiency, optics, aging, and operating temperature. Use the conversion as an estimate and verify with manufacturer specs for critical applications.