Get a quick, visual estimate of how much natural light a translucent roof or skylights will bring into a building.
Estimate only. Results are indicative, based on the values you enter and simple standard methods. Always confirm with the product datasheet, applicable codes and a qualified engineer before design or purchase.
How the estimate works
Average indoor daylight ≈ outdoor illuminance × (skylight area ÷ floor area) × sheet light transmission × utilisation factor. The utilisation factor accounts for light lost to roof depth, dirt, structure and room surfaces; 0.5 is a common starting assumption.
Keep in mind
- Light transmission varies by sheet thickness, structure and colour — use your product’s datasheet value.
- More skylight area also means more solar heat gain; diffused or tinted sheets can reduce glare and heat.
- For detailed design, use professional daylight simulation software.


