PPFD to DLI calculator
Turn a canopy PPFD reading into a daily light total and compare schedules.
Use the result as a starting point.
Enter measured values, check the units, and keep the assumptions beside the answer. This tool supports a growing decision; it does not replace a calibrated meter, a product label, or observation of the crop.
Use both measurements: PPFD checks intensity at a point; DLI checks the total over the day.
Keep a dark period appropriate for the crop.
How to use this tool
Use this focused conversion when you already have a canopy PPFD reading and want to compare daily light schedules.
- Enter measured canopy PPFD and the number of light hours in the daily cycle.
- Enter the values, check the units, and select Calculate.
- Read the result as a planning estimate, then compare it with the crop and system.
Formula or reference method
DLI = PPFD x photoperiod hours x 3,600 / 1,000,000.
Worked example
A reading of 150 PPFD for 14 hours gives 150 x 14 x 3,600 / 1,000,000 = 7.56 mol/m2/day.
Understanding the result
Use the result to compare schedules. Equal DLI does not guarantee equal plant response if intensity, heat, or uniformity changes.
Assumptions and limits
This is a canopy-light estimate and does not measure fixture output, edge falloff, spectrum, or light stress.
Common mistakes
Do not enter fixture wattage, lux, or a photoperiod greater than 24 hours in place of PPFD.