Lighting Calculator
Determine the optimal luminous flux (lumens) and power consumption for any space using industry-standard illuminance targets.
Darker walls absorb more light, requiring more lumens.
Standard LED: ~90, CFL: ~60, Incandescent: ~15
Total Required Output
Recommended Fixtures
How is this calculated?
Total Lumens = Area (sq m) × Target Lux × Wall Factor
We calculate the room area in square meters and multiply by the target illuminance (Lux). The "Wall Color" adjusts for light absorption: Darker walls absorb more light, requiring higher lumen output to achieve the same brightness.
Methodology
This calculator utilizes the Lumen Method (or Zonal Cavity Method approximation) to determine the total luminous flux required to achieve a target illuminance level on the working plane.
1. Target Illuminance (Lux)
Different activities require specific light levels. We recommend standard lux levels based on IESNA (Illuminating Engineering Society of North America) guidelines:
- Living Areas (150 Lux): General ambient lighting for relaxation.
- Kitchen/Workspaces (300-500 Lux): Higher intensity for task performance and safety.
- Detailed Work (750+ Lux): For precision tasks like drafting or sewing.
2. Room Surface Reflectance
Light is absorbed by surfaces. Darker walls absorb significantly more light than lighter ones, requiring a higher initial lumen output to maintain the same illuminance level.
*Wall Factor accounts for light absorption (e.g., 1.5x multiplier for dark surfaces).
3. Efficacy & Wattage
Wattage is calculated based on the Luminous Efficacy of the light source. Modern LED technology typically achieves 80-120 lumens per watt (lm/W), whereas legacy incandescent bulbs only achieve ~15 lm/W.