How the lux calculator works
Lux measures illuminance, or how much light reaches a surface. The basic relationship is simple: lux equals lumens divided by area. A 50 m2 office targeting 500 lux therefore needs around 25,000 lumens before detailed utilisation and maintenance factors are applied.
The calculator starts with the application because the correct lighting level depends on the task. A corridor, meeting room, retail display and inspection area should not be treated as the same type of space.
Why lux alone is not enough
Two schemes can both measure 500 lux and still feel completely different. Glare control, spacing, optical distribution, ceiling height, surface reflectance and the working plane all affect whether the space is comfortable and compliant.
For screen-based workplaces, controlled optics and low glare performance are often more important than simply increasing output. That is why office lighting levels should be checked alongside UGR, uniformity and luminaire positioning.
From benchmark to specification
Once the target lux level is known, the next step is selecting luminaires that can deliver the required output cleanly. Open-plan offices often suit linear luminaires or suspended systems, while circulation areas, retail spaces and compact rooms may use LED downlights, track lighting or wall-mounted luminaires.
The product selection in the calculator is a starting point for that discussion, not a substitute for final design validation.
General office areas300-500 lux
Computer workstations300-500 lux
Drawing, inspection or detailed task areas500-1000+ lux
Retail spaces and showrooms500-1000 lux
Warehouses, storage and distribution areas100-300 lux
Corridors, stairs and circulation spaces50-200 lux
Plant rooms and building services areas100-300 lux
Common mistakes when using lux targets
- Using a single average lux target without checking glare and uniformity.
- Ignoring the working plane, especially for desks, benches and inspection tasks.
- Choosing fittings by lumen output only, without reviewing optics or spacing.
- Over-lighting a space when better distribution would solve the problem.
Where CIBSE and BS EN guidance fits
CIBSE recommended lighting levels and BS EN 12464-1 workplace lighting guidance are useful references for early planning. They help identify the likely illuminance range for a task, but the final requirement still depends on the project context.
For formal specification, the lux target should be checked against the room geometry, mounting height, controls strategy, emergency lighting layout and the relevant project standard.
Related lighting calculators
If you already know the target lux level and want a deeper fitting estimate, use the Lighting Design Calculator. For output-led planning, use the Lumens Calculator. For workplace running costs and payback, use the Office Lighting Calculator.
For projects moving beyond benchmark guidance, Lumenloop can provide product data, circularity notes and technical files before quotation.
