Watts to Lux Calculator
Find out how much light will hit a surface based on the wattage of your light source and the size of the room.
E_v(lx) = [P(W) × η(lm/W)] / A(m²)
10W LED (90 lm/W) over 10 m² = (10 * 90) / 10 = 90 lux
How do I convert watts to lux?
To convert watts to lux, you need the luminous efficacy of the bulb and the surface area. Formula: Lux = (Watts × Luminous Efficacy) / Area.
What is the standard efficacy for an LED?
A standard consumer LED bulb has an efficacy of about 80 to 100 lumens per watt (lm/W).
Why do I need to know the area?
Lux measures the density of light on a surface. The larger the area you spread the light over, the lower the lux (brightness on the surface) will be.
🔗 Related Calculators
📐 Formula
E_v(lx) = [P(W) × η(lm/W)] / A(m²)
📝 Example Calculation
10W LED (90 lm/W) over 10 m² = (10 * 90) / 10 = 90 lux
❓ Frequently Asked Questions
How do I convert watts to lux?▼
To convert watts to lux, you need the luminous efficacy of the bulb and the surface area. Formula: Lux = (Watts × Luminous Efficacy) / Area.
What is the standard efficacy for an LED?▼
A standard consumer LED bulb has an efficacy of about 80 to 100 lumens per watt (lm/W).
Why do I need to know the area?▼
Lux measures the density of light on a surface. The larger the area you spread the light over, the lower the lux (brightness on the surface) will be.