Lighting Design Calculator
Calculate the number of light fixtures needed using the lumen method: N = (E × A) / (F × UF × MF).
Inputs
lux
IES Handbook: corridors 100 lux; warehouse 100–200 lux; office 300–500 lux; labs 750–1,000 lux
sq ft
lm
ft
Results
Fixtures Needed
21 fixtures
Actual Illuminance
504 lux
Total Lumens105,000 lm
Lighting Power Density0.98 W/ft²
How to Use This Calculator
- Enter the Target Illuminance in lux: office work ≈ 500 lux, warehouse ≈ 200 lux, precision tasks/labs ≈ 750–1000 lux.
- Enter the Room Area in m² and the mounting height above the work plane in meters.
- Enter the Lumens per Fixture from the manufacturer's datasheet (initial lumens, not depreciated).
- Set the Utilization Factor (0.4–0.7) based on room shape and surface reflectances — use the fixture's photometric data for accuracy.
- Set the Maintenance Factor (0.6–0.8): clean environments ≈ 0.8, dusty or industrial ≈ 0.6.
- Read the number of Fixtures Needed and the Actual Illuminance — adjust fixture layout to achieve target lux while staying within energy code limits (Lighting Power Density in W/ft²).
Ad Placeholder
Related Calculators
Demand Load Calculator
Calculate residential service demand load per NEC Article 220: general lighting, appliances, HVAC, and service size.
Cable Ampacity Calculator
Determine cable ampacity with NEC derating factors for temperature, conduit fill, and continuous loads.
Emergency Generator Calculator
Size emergency generators with altitude and temperature derating, fuel consumption, and runtime estimates.
Ad Placeholder