Calculator Inputs
Pick a method, enter values, and submit. Results appear above this form and below the header.
Formula Used
Shade % = ((Incident Light − Transmitted Light) ÷ Incident Light) × 100
Transmission % = (Transmitted Light ÷ Incident Light) × 100
Combined Shade % = [1 − (1 − Single Layer Shade) Layers] × 100
Required Shade % = 100 − (Target Transmitted Light ÷ Incident Light × 100)
The calculator uses ratios, so lux, foot-candles, or PPFD all work as long as incident and transmitted inputs use the same unit.
How to Use This Calculator
- Select the calculation mode that matches your situation.
- Enter your light values, cloth rating, or target transmission goal.
- Choose a unit and optional garden use profile.
- Adjust performance factor or safety margin when needed.
- Press Calculate to show results above the form.
- Review the summary, graph, and layer preview table.
- Use the CSV or PDF buttons to save the result.
Example Data Table
| Use Case | Typical Shade % | Expected Transmission % | General Note |
|---|---|---|---|
| Hardening-off seedlings | 20–30% | 70–80% | Good for gradual sun exposure. |
| Leafy greens in summer | 30–40% | 60–70% | Reduces scorching and stress. |
| General nursery area | 40–50% | 50–60% | Useful for balanced protection. |
| Greenhouse summer control | 50–60% | 40–50% | Helps manage heat load. |
| Orchids and delicate plants | 60–75% | 25–40% | Supports lower-light species. |
| Very harsh sun protection | 80%+ | Below 20% | Check crop tolerance carefully. |
FAQs
1. What does shade cloth percentage mean?
It shows how much incoming light the cloth blocks. A 40% cloth blocks about 40% of sunlight and allows roughly 60% to pass through.
2. Can I use lux, foot-candles, or PPFD?
Yes. Because the calculation is ratio-based, any light unit works. Just keep both incident and transmitted values in the same unit.
3. Why do multiple layers increase shade quickly?
Each layer filters the light that already passed through the previous layer. That compounding effect makes total transmission drop faster than simple addition suggests.
4. What is the performance factor for?
It adjusts the named cloth rating for real-world conditions. You can lower it for worn materials or raise it slightly for a cleaner, tighter installation.
5. How much shade is good for vegetables?
Many vegetables perform well around 30% to 50% during intense heat. Exact needs vary by crop, season, humidity, and local sunlight intensity.
6. Should I add a safety margin?
A small safety margin can help when midday sun is extreme or when target conditions are strict. Use it carefully because too much shade can slow growth.
7. Why might measured shade differ from the label?
Age, dust, cloth color, sun angle, meter accuracy, and installation tension can all change real transmission. Field measurements often provide the most practical answer.
8. Can this calculator help with patios and pergolas too?
Yes. The same transmission logic works for comfort shading. You can estimate how much brightness and glare your outdoor sitting area will retain.