Watts to Lumens conversion

Electric power in watts (W) to luminous flux in lumens (lm) conversion calculator and how to convert.

Enter the power in watts, the luminous efficacy in lumens per watt and press the Calculate button:


Watts to Lumens calculation formula

Energy saving lamps have high luminous efficacy (more lumens per watt).

The luminous flux Φv in lumens (lm) is equal to the power P in watts (W) times the efficacy η in lumens per watt (lm/W):

Φv(lm) = P(W) * η(lm/W)

Luminous efficacy conversion table

Light type Typical luminous efficacy (lumens/watt)
Tungsten incandescent light bulb 12.5-17.5 lm/W
Halogen lamp16-24 lm/W
Fluorescent lamp45-75 lm/W
LED lamp80-100 lm/W
Metal halide lamp75-100 lm/W
High pressure sodium vapor lamp85-150 lm/W
Low pressure sodium vapor lamp100-200 lm/W
Mercury vapor lamp 35-65 lm/W

Give Us Your Feedback