Supplemental Lighting Calculator

Calculate grow light fixture count and energy cost to reach target DLI and PPFD for greenhouse crops.

Inputs

Growing Area

sq ft

Target PPFD

µmol/m²/s

Natural DLI

mol/m²/d

Photoperiod

hrs

Fixture Type

Watts per Fixture

Fixture PPFD Output

µmol/m²/s

Electricity Cost

$/kWh

Tab to move between fields

Results

Fixtures Needed

Monthly Electric Cost

$1,161.22

≈ 9 pairs of sneakers

Target DLI23 mol/m²/d

Supplement DLI Needed13 mol/m²/d

Required Supplemental PPFD226 µmol/m²/s

Total Wattage20,160 W

Daily Energy322.56 kWh

How to Use This Calculator

Enter your total growing area in sq ft and the target PPFD (µmol/m²/s) for your crop — leafy greens ~200, tomatoes ~400–600.
Enter the natural DLI (mol/m²/d) available from sunlight in your location and season, and your desired total photoperiod in hours.
Select fixture type (LED, HPS, or CMH) and enter each fixture's wattage and PPFD output at canopy level.
Enter your electricity cost per kWh to calculate Monthly Electric Cost.
Review Fixtures Needed, Total Wattage, and Daily Energy (kWh) to plan your electrical service requirements.

How the result changes with Growing Area

Growing Area	Fixtures Needed	Monthly Electric Cost
5,009	314	$5,787.65
17,507	1,095	$20,183.04
32,504	2,032	$37,453.82
45,001	2,813	$51,849.22

What each input means

Growing Area: Total canopy area requiring supplemental light.
Target PPFD: Desired photosynthetic photon flux density for the crop.
Natural DLI: Daily light integral from sunlight in your location and season.
Photoperiod: Total hours of light (natural + supplemental).
Fixture Type: Light technology type.
Watts per Fixture: Power draw of each light fixture.
Fixture PPFD Output: PPFD output of each fixture at canopy.
Electricity Cost: Cost per kilowatt-hour.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Growing Area = 1000, Target PPFD = 400, Natural DLI = 10, Photoperiod = 16 = 8 input(s) provided
Calculate Fixtures Needed
Fixtures Needed
63 = 63
Calculate Monthly Electric Cost
Monthly Electric Cost
1161.22 = $1,161.22
Calculate Target DLI
Target DLI
23 = 23
Calculate Supplement DLI Needed
Supplement DLI Needed
13 = 13

Engine last updated August 5, 2026. Checked against 1 independently-derived test — how we verify calculators.

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