How does the Daylight Factor Calculator work?

Daylight factor = (indoor illumination / outdoor illumination) × 100% Then: Values: 5% (well-lit) Then: Depends on window size, orientation, obstruction.

Can you give an example of how to use the Daylight Factor Calculator?

Example: Input Indoor illumination 100 lux, outdoor 5000 lux gives a result of Daylight factor = 2% (borderline, likely needs supplementary lighting) (Typical office).

Is the Daylight Factor Calculator free to use?

Yes — completely free with no registration, download, or subscription required. All calculations happen instantly in your browser.

How accurate is the Daylight Factor Calculator?

Our Daylight Factor Calculator uses verified mathematical formulas and is accurate to multiple decimal places. Results are calculated in real-time using the same methods used by professionals.

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Daylight Factor Calculator

Workplane Illuminance (lux)

Outside Illuminance (lux)

Daylight factor measures indoor daylight availability as percentage of outdoor illuminance. It determines whether artificial lighting is required.

Difficulty:intermediate

References

›Daylight Factor — Wikipedia

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Daylight Factor Calculator

Daylight Factor Calculator

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Daylight Factor Calculator