Lighting
Light Calculator: Estimate PPFD and DLI from Wattage and Height
Enter your light specs — the calculator estimates PPFD and DLI and tells you whether your light level matches the current stage.
Light Calculator
Estimate PPFD & DLI
SteerMind AI can diagnose this exact issue from a symptom description or leaf photo — and give you a concrete action plan in seconds.
Understanding PPFD and DLI
PPFD (Photosynthetic Photon Flux Density) measures the number of photosynthetically active photons hitting one square metre per second — expressed in µmol/m²/s. It's the key instantaneous measure of light intensity.
DLI (Daily Light Integral) sums those photons over the entire day. Formula: DLI = PPFD × hours × 3600 ÷ 1,000,000 (in mol/m²/d). DLI is the better comparison metric because it accounts for photoperiod.
FAQ
How accurate is this estimate?
The calculation uses typical efficiency values and beam angles. For precise readings, use a PAR meter at canopy level. This estimator provides solid orientation but is not a replacement for actual measurement.
Why do seedlings need less light?
Young plants have less leaf mass and underdeveloped root systems. Too much light causes photostress and bleaching before the plant can use it.