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Light reference

DLI Calculator & Chart

Calculate daily light integral (DLI) from PPFD and light hours, or plan daily light by plant age.

For a worked example and the limits of a daily total, read Demystifying DLI.

DLI Calculators

Convert between canopy PPFD, photoperiod, and daily light integral.

PPFD → DLI

Use a meter reading and light schedule to estimate the daily total.

mol/m²/day

DLI → PPFD

Use a daily target and photoperiod to find the average canopy PPFD.

µmol/m²/s
This is the average canopy PPFD needed across the whole lit period.

Cannabis grow room tool

DLI Recommendations by Plant Age

Daily Light Integral targets from seedling through maturing. Use these as a planning baseline for normal growth without added CO2.

45peak mol/m²/day

Recommended DLI by week

Recommended DLI Light cycle

DLI formula: DLI = PPFD × photoperiod (hours) × 3600 / 1,000,000. For example, 600 µmol/m²/s for 18 h is 600 × 18 × 3.6 / 1000 = 38.9 mol/m²/day.