About Lighting Calculator
The lumen method estimates the number of light fittings needed for an average illuminance on the working plane. N = E × A ÷ (Φ × UF × MF), where E is the target in lux, A the floor area, and Φ the lumens per fitting. The utilization factor covers light lost to walls and ceiling, and the maintenance factor covers dirt and lamp aging. Typical targets are 100 to 150 lux for corridors, 300 to 500 for offices, and 500 or more for detailed work.
How to use Lighting Calculator
- Fill in "Room length", "Room width", "Target illuminance" and "Lumens per fitting", and the other options.
- The result appears below and updates as you type.
- Copy the result with the copy button, or download it as a file where that is offered.
Questions about Lighting Calculator
What is the difference between lumens and lux?
Lumens measure the total light a source emits. Lux measures how much of that light lands on a surface: one lux is one lumen per square metre. The same lamp gives more lux in a small room than in a large one.
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