How Many Lumens Equal One Watt?
Lumens and watts measure two different things. A watt measures the amount of power that is used. Lumens measure the flux of a produced light from it's source or received by a surface. Therefore, the two can't be converted.
One lumen is equal to approximately 0.000000146 watts. That is lumen per square footage, and watts per square centimeter.
In measuring light, 1 lumen is the equivalent of 680 lumen. This measurement is assuming the eye is operating at its peak.