how to calculate how much light plants are getting indoor lighting led?

To calculate the light intensity for indoor plants under LED lighting, use a lux meter. Place the meter at plant canopy height and measure the illuminance in lux. Different plants have varying light requirements, but as a general guide, low-light plants need 200-400 lux, moderate-light plants require 400-1000 lux, and high-light plants thrive in 1000-2000 lux. Adjust the LED light intensity or duration based on these readings and the specific needs of your plants for optimal growth.