Creator utility lab
DLI Calculator (Daily Light Integral)
Intensity × hours × 0.0036 — the light number plants actually live on.
Add up a day of light like a plant does
Intensity times hours times 0.0036 — the daily light integral, measured in moles of photons.
Plants integrate: a dim lamp for long hours can feed a plant as well as strong light briefly, and DLI is the number that makes the trade visible.
- Hit a lettuce-friendly DLI of 14 two different ways.
- Halve the intensity — how many extra hours keep the DLI even?
Plants integrate light over the whole day, so a dim lamp for long hours can feed a plant as well as strong light briefly. DLI = PPFD × hours × 0.0036, in moles of photons per square meter per day.
Lettuce wants roughly 12–17 DLI, herbs a bit less, fruiting crops far more. Slide your lamp's numbers and see which crops your setup honestly supports.
What DLI do houseplants need?
Most tolerate 4–8; growth improves visibly toward the top of the range.
My lamp lists lumens, not PPFD — now what?
Lumens measure human brightness. For plants, look for a PPFD map in the lamp's spec sheet.