Calculator Inputs
Quick guidance (very general)
- Seedlings: roughly 100–300 µmol/m²/s.
- Vegetative: roughly 200–600 µmol/m²/s.
- Flowering: roughly 400–900 µmol/m²/s.
Why presets differ
Lux is biased toward green light. Two lamps can show the same lux but deliver different PPFD. Use a manufacturer PPF chart when available.
Example data table
| Lux (lx) | Preset | Factor | Photoperiod (h) | PPFD (µmol/m²/s) | DLI (mol/m²/day) |
|---|---|---|---|---|---|
| 15,000 | Cool white LED | 0.0140 | 16 | 210.0 | 12.10 |
| 25,000 | Warm white LED | 0.0120 | 18 | 300.0 | 19.44 |
| 60,000 | Daylight / Sunlight | 0.0185 | 10 | 1,110.0 | 39.96 |
Examples are approximations for demonstration purposes.
Formula used
1 Convert lux to PPFD using a spectrum factor:
PPFD (µmol/m²/s) = Lux × Factor
2 Estimate DLI using the photoperiod:
DLI (mol/m²/day) = PPFD × (Hours × 3600) ÷ 1,000,000
Factor is lamp-dependent. If you only have lux, choose the closest preset. For best accuracy, measure with a quantum sensor or derive the factor from the fixture datasheet.
How to use this calculator
- Take a lux reading at canopy height, centered under the lamp.
- Select the light source preset closest to your fixture.
- If you know your factor, choose Custom and enter it.
- Enter your daily photoperiod to compute DLI.
- Click Calculate to view PPFD and DLI above the form.