Illuminance Calculator

Calculate average illuminance using the lumen method with maintenance factor, utilization factor, and room index — free lighting design tool

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RI = (L \u00D7 W) / ((L + W) \u00D7 (H - Wp))

E = (N \u00D7 F \u00D7 U \u00D7 M) / (L \u00D7 W)

Room Parameters

Room Length L (m)

Room Width W (m)

Ceiling Height (m)

Work Plane Height Wp (m)

Mounting Height H (m)

Ceiling Reflectance (%)

Wall Reflectance (%)

Floor Reflectance (%)

Lighting Parameters

Lamp Lumens F (lm)

Number of Luminaires N

Maintenance Factor M (0.6-0.8)

Results

Average Illuminance E

310 lx

Room Index RI

2.22

Utilization Factor U

59.0%

Required Luminaires by Target