PBFD / DLI Calculator

Please enter the size area you want to grow in, or the size footprint you're looking for each light to cover:

Length:		feet inches meters cm
Width:		Calculate
Photobiological Photon Flux Density (PBFD) Photobiological Daily Light Integral (DLI)Running 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 hours per day

Footprint area:
Light Model	Hanging Height (inches)	Average PBFD (μmol/m2/s)
PhytoMAX-4 2S	-	-
PhytoMAX-4 4S	-	-
PhytoMAX-4 8S	-	-
PhytoMAX-4 12S	-	-
PhytoMAX-4 16S	-	-
PhytoMAX-4 20S	-	-
PhytoMAX-4 24S	-	-

Hanging height is the height the light needs to be hung above the average top of the canopy to allow the light to spread out and cover the footprint you specified, and does not vary with the light model. For larger areas, using muliple smaller lights (each with a smaller footprint) reduces the required hanging height. PhytoMAX-4 lights can be flush-mounted to the ceiling and are only 4.5" / 11cm thick.

The PBFD levels given are the average for every square inch of the footprint you specify. All light intensity calculations assume reasonably-reflective walls around the footprint and/or adjacent lights on identical footprints. This calculator is intended to guide you to the right size light for your situation, but we're always here to help- you can always contact us for advice.

We have custom, proprietary light modeling software that can show you guaranteed light intensity levels for every square inch of your growing area, or even every cubic inch from top to bottom. Contact us through email or phone or schedule a large-project consultation.

Recommended PBFD Ranges

The ranges given below are guidelines based on our years of experience. You can go lower or higher in some circumstances; you can always contact us if you want to talk about unusual set-ups.

The "Min" light level is the minimum we would think you would be happy with for decent results; "Typical" is what we would generally recommend and "Max" is on the higher end of what we would recommend. PhytoMAX-4 lights can be dimmed, so you can always get a bit more power than you need and experiment.

Recommended μmol/m2/s PBFD
Growth Stage	Min	Typical	Max
Cloning	50	75 - 100	150
Seedlings	200	300 - 600	700
Vegetative	200	300 - 600	800
Flower- 12 hrs/day No CO2	350	600 - 750	950
Flower- 12 hrs/day With CO2	800	900 - 1300	1800
Flower- 12 hrs/day With CO2 Extreme	1200	1500 - 1800	2500 **
Flower- 20 hrs/day (autoflower) No CO2	200	350 - 450	600
Flower- 20 hrs/day (autoflower) With CO2	450	600 - 775	1000

** This light level is only recommended for experimentation or research purposes- it is not recommended for a production facility. Driving plants with that much light requires a lot of attention to fertilization, CO₂ and environmental conditions- it is much more likely that something will go wrong and cause complete crop loss. We've tested light levels like this ourselves- which is why we don't recommend it in general, though we did get 137 grams/ft² for a 6' X 6' area at 2200 μmol/m²/s PBFD. PhytoMAX-4's unique design can deliver even higher light levels if you desire to really push limits, but we haven't seen any practical benefit yet.