Daily Light Integral (DLI) Calculator
Enter the light intensity in μmol/m²/s.
Enter the number of light hours per day.
Calculated as: (PPFD × Photoperiod × 3,600) ÷ 1,000,000
Enter the light intensity in LUX.
Select your light source.
Calculated as: LUX ÷ Conversion Factor
Indoor DLI is calculated below from PPFD & Photoperiod.
Helps identify hotspots or dark spots for optimal grow light positioning.
Created by James S. Lockwood
With a background in botany and ecological sciences, James specializes in creating practical tools and resources to help gardeners, farmers, and plant enthusiasts optimize their green spaces.
What is a DLI Calculator?
A DLI Calculator (Daily Light Integral Calculator) helps growers, farmers, and indoor gardeners determine the total amount of light their plants receive per day. This is crucial for optimizing plant growth, improving yields, and ensuring proper light exposure.
By using a DLI Calculator, you can adjust lighting conditions to meet the needs of different plant types, whether they are low-light plants (ferns, orchids), medium-light plants (lettuce, herbs), or high-light plants (tomatoes, cannabis).
Why is DLI Important for Plants?
DLI (measured in mol/m²/day) represents the total amount of Photosynthetically Active Radiation (PAR) a plant receives over a 24-hour period. It determines plant health, photosynthesis efficiency, and overall growth rate.
✅ Key Benefits of DLI Calculation:
- Optimizes plant growth and yield
- Helps adjust artificial lighting for indoor plants
- Ensures plants receive the right amount of light per day
- Supports different plant species based on their light requirements
How to Calculate DLI?
DLI is calculated using PPFD (Photosynthetic Photon Flux Density) and Photoperiod (light hours per day) using the formula:
Steps to Calculate DLI:
1️⃣ Find PPFD (μmol/m²/s) – Measure the light intensity using a quantum light meter.
2️⃣ Determine Photoperiod (hours/day) – Count how many hours of light the plant receives per day.
3️⃣ Apply the DLI formula – Multiply PPFD by photoperiod and 3,600, then divide by 1,000,000.
💡 Example:
- PPFD = 500 μmol/m²/s
- Photoperiod = 16 hours
- DLI = (500 × 16 × 3,600) ÷ 1,000,000
- DLI = 28.8 mol/m²/day
This means your plants receive 28.8 mol/m²/day, which is ideal for high-light plants like tomatoes or cannabis.
How to Calculate DLI from PAR?
PAR (Photosynthetically Active Radiation) is the range of light (400–700 nm) used by plants for photosynthesis. To calculate DLI from PAR, follow these steps:
DLI Calculation from PAR Formula:
Steps:
✔ Measure PAR (μmol/m²/s) using a light meter
✔ Determine the Photoperiod (hours of light/day)
✔ Use the formula to find DLI
💡 Example:
- PAR = 400 μmol/m²/s
- Photoperiod = 14 hours
- DLI = (400 × 14 × 3,600) ÷ 1,000,000 = 20.16 mol/m²/day
Recommended DLI Levels:
Low-Light Plants
🌿 Ferns, Orchids
☀️ 5-10 DLI (mol/m²/day)
Medium-Light Plants
🌿 Lettuce, Herbs
☀️ 10-20 DLI (mol/m²/day)
High-Light Plants
🌿 Tomatoes, Cannabis
☀️ 20-40 DLI (mol/m²/day)
🔹 Tip: If your DLI is too low, increase PPFD or photoperiod. If it’s too high, decrease light intensity or exposure time.
How to Calculate DLI at Pulsed Light Plant Growth?
Pulsed light technology is an advanced method where plants receive light in short bursts rather than a continuous stream. This method enhances efficiency while reducing energy costs.
To calculate DLI in pulsed light plant growth, you need to consider:
✔ PPFD during the light pulse
✔ Pulse duration (in seconds per cycle)
✔ Photoperiod (total hours of exposure per day)
Pulsed DLI Formula:
Why Use This DLI Calculator?
✅ Easy-to-Use Interface: Just enter PPFD & Photoperiod to get DLI
✅ Compares Indoor & Outdoor DLI: Ensures the right lighting setup
✅ Grow Light Optimization Suggestions: Adjust lighting if DLI is too high/low
✅ Converts LUX to PPFD: Helps with different light sources
Frequently Asked Questions (FAQs)
❓ What is the ideal DLI for houseplants?
Houseplants thrive between 5-15 mol/m²/day, depending on species. Low-light plants like ferns require 5-10 mol/m²/day, while high-light succulents need 10-20 mol/m²/day.
❓ How do I increase DLI for my plants?
You can increase DLI by:
✔ Increasing light intensity (PPFD)
✔ Extending photoperiod (light hours per day)
✔ Using grow lights with higher output
❓ Can I use LUX to calculate DLI?
Yes! You can convert LUX to PPFD first using conversion factors:
- Sunlight: LUX ÷ 54
- LED Grow Lights: LUX ÷ 65
- HPS Lights: LUX ÷ 80
Then, use the DLI formula to get your results.
Disclaimer for DLI Calculator
This DLI Calculator is for informational purposes only. Results may vary based on environmental factors, light sources, and plant-specific needs. Always verify light intensity with a PAR meter for precise measurements.
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