Lumens to Watts Calculator
Lumens measure brightness and watts measure the power a bulb uses. How many watts you need for a given number of lumens depends on the bulb technology.
Type a number and the answer appears straight away.
Your answer
800 lumens needs about8.9 W
- Efficacy assumed
- 90 lumens per watt
Efficacy is a typical figure for each technology. Check the Lighting Facts label on the box for the exact value.
| Bulb type | Watts needed |
|---|---|
| LED | 8.9 |
| CFL (compact fluorescent) | 13.3 |
| Halogen | 40 |
| Incandescent | 53.3 |
The math behind it: Lumens to Watts
watts = lumens / efficacy (lumens per watt)
An old 60-watt incandescent bulb gives about 800 lumens. An LED produces the same light from roughly 9 watts, which is why packaging now leads with lumens.
Common questions
How many lumens do I need for a room?
A rough guide is 10 to 20 lumens per square foot for living areas and 70 to 80 for kitchens and work surfaces.
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