💡 Grow Light Coverage
Watts per sq ft and coverage area for indoor growing
About this calculator
The Grow Light Coverage calculator sizes lighting for indoor growing. Enter your grow area and the light's rated coverage or PPFD at hanging height; it shows how many fixtures you need, optimal hanging distance, and daily light integral from your photoperiod. Seedlings stretch and get leggy under weak light long before they die.
Tip: measure with a cheap PAR meter or phone app rather than trusting the box — advertised coverage areas are almost always optimistic, especially at the edges.