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Watts to Lux Calculator
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Calculate illuminance (Lux) from light source power and area.
Inputs
Power (Watts)
Luminous Efficacy (lm/W)
Surface Area (m²)
Reset
Illuminance
Lux
-
lx
Total Lumens
-
lm
About this calculator
Quick Reference
Incandescent
~15 lm/W
Compact Fluorescent
~60 lm/W
LED
~90+ lm/W
Overview
This calculator estimates the lux level on a surface based on the power of the light source, its luminous efficacy, and the surface area.
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Pro Tips
Luminous efficacy determines how many lumens are produced per watt.
LEDs have high efficacy (~80-150 lm/W), while incandescent bulbs are low (~15 lm/W).
Lux = Lumens / Area (m²).
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Fun Facts
"Direct sunlight can provide up to 100,000 lux."
"Standard office lighting is usually around 300-500 lux."
"Moonlight is only about 0.05 to 0.2 lux."
Formula: Lux = (W × lm/W) / m²
