Lux to PPFD converter

Enter a lux reading and pick your light source. The converter divides by a typical lux-to-PPFD factor for that spectrum. This is an estimate, not a calibrated measurement.

FAQ

How do you convert lux to PPFD?

Divide the lux reading by a conversion factor that depends on the light source spectrum. Each source type has a different factor because lux is weighted for the human eye, not for photosynthesis.

Is a lux-to-PPFD conversion accurate?

It is an approximation. A single factor cannot capture every spectrum, and phone lux sensors vary between models. For measurements that matter, use a calibrated quantum sensor.

Conversion factors come from Apogee Instruments' published table: sunlight 54, HPS 77 (dual-ended 1000 W), metal halide 71. Apogee does not publish a factor for white LED — white LED spectra vary too much between products for one number to hold — so the 67 used here is a commonly cited approximation and is the least reliable option in this list. Any lux-based estimate is an approximation; a quantum sensor is the only way to know.