Lux to PPFD Calculator
This calculator helps you estimate the PPFD (Photosynthetic Photon Flux Density, measured in µmol/m²/s) from a given lux reading. While lux measures how bright a light appears to the human eye, PPFD measures the number of light particles (photons) in the 400 - 700 nm range, the part of the spectrum that plants use for photosynthesis. Because different types of lights (such as sunlight, LEDs, fluorescent lamps, or HPS grow lights) emit light with different spectral compositions, converting lux to PPFD requires knowing what kind of light source you're using. This tool allows you to choose a light type and apply an appropriate conversion factor, giving you a more accurate estimate of the light available to your plants.
Enter your light intensity in lux:
Select your light source type:
What is PPFD?
PPFD (Photosynthetic Photon Flux Density) measures how many photons in the PAR range (400 - 700 nm) hit a square meter each second, expressed in µmol/m²/s.
How the Conversion Works
Since lux is based on human brightness perception and PPFD is based on photon count, we use approximate conversion factors depending on the light source spectrum.