UK commercial lighting benchmark

Lux calculator: estimate light levels

Choose a room type and enter its area to estimate a starting lux level and the lumens required at the working plane before optics, maintenance and spacing allowances.

Space type Room area Lux target

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Lux calculator: estimate a starting light level and baseline lumen requirement.

This lux calculator provides an early planning benchmark for offices, warehouses, retail areas, circulation spaces, plant rooms and other commercial interiors. It multiplies the room area by the selected lux target to show the baseline lumen requirement at the working plane and relevant Lumenloop luminaires.

It assumes the selected light level applies across the entered floor area. Fitting output, ceiling height, reflectance, optics and spacing are not included in that surface-demand figure.

The result is an early specification reference. Photometric files, glare, ceiling details, reflectance values and emergency lighting must still be considered for a final lighting design.

Lux, made visible

The same light, spread over more space.

Lux describes how much light reaches a surface, not simply how much a fitting produces. Double the lit area while keeping the total lumens fixed and the average lux halves.

The relationship lumens ÷ area = lux

Compact area10,000 lm ÷ 20 m² = 500 lux

Twice the area10,000 lm ÷ 40 m² = 250 lux

Typical planning ranges

Use the range to choose a sensible starting point, then check the exact visual task and project standard.

General office areas300–500 lux

Computer workstations300–500 lux

Drawing, inspection or detailed task areas500–1,000+ lux

Retail spaces and showrooms500–1,000 lux

Warehouses, storage and distribution areas100–300 lux

Corridors, stairs and circulation spaces50–200 lux

Plant rooms and building services areas100–300 lux

These figures are early planning benchmarks, not a substitute for a project-specific lighting design or the applicable standard.

Understanding lux and lumens

Lux measures illuminance: the amount of light reaching a surface. Lumens measure the total light output from a luminaire. One lux is one lumen per square metre, so a 50 m2 room planned at 500 lux needs 25,000 lumens at the working plane before design allowances.

The selected task establishes the planning benchmark. This estimator does not measure a completed room; installed illuminance should be checked with a light meter or established through project-specific photometric data.

From benchmark to lighting design

A lux target is only one part of a comfortable, compliant scheme. Uniformity, glare, mounting height, optics, controls and the working plane all affect how useful the light will feel.

Do not rely on a single average lux target without checking glare and uniformity.
Set the correct working plane for desks, benches and inspection tasks.
Compare luminaires by distribution and spacing, not lumen output alone.
Avoid over-lighting where better distribution would solve the problem.

CIBSE recommended lighting levels and BS EN 12464-1 workplace guidance are useful references for early planning. A formal specification must also reflect room geometry, the visual task, mounting height, controls, emergency lighting and the applicable project standard.

Turn the estimate into a specification

Use the target output to compare LED panel lighting for broad, uniform coverage, alongside linear lighting and commercial downlights. The estimator cannot judge beam angle, emergency escape routes, rack shadowing or exact luminaire spacing, so those checks should follow as the project develops.

For fitting count and spacing, use the Lighting Design Calculator. For output-led planning, use the Lumens Calculator; for workplace running costs and payback, use the Office Lighting Calculator.

Compare the result with the specific needs of office lighting, warehouse and industrial lighting, retail lighting or emergency lighting. Lumenloop can provide product information, circularity notes and technical files before quotation.

Lux level questions

Concise answers for early-stage lighting planning. Open a question for the detail.

How do you calculate a lux level?

For an early room estimate, multiply the target illuminance in lux by the lit area in square metres. A 500 lux target across 50 m2 gives 25,000 lumens before allowances for optics, maintenance and room geometry.

What is the recommended lux level for office lighting?

General office lighting is commonly planned around 300–500 lux, depending on the task, screen use and visual comfort requirements. Detailed drawing or inspection work may need a higher target.

What is the difference between lumens and lux?

Lumens measure the total light output from a luminaire. Lux measures how much light reaches a surface. A high-lumen product can still deliver poor lux levels if the optics, spacing or mounting height are wrong.

Are CIBSE recommended lighting levels mandatory?

CIBSE guidance is widely used for UK lighting design, but each project should be checked against the applicable standards, risk profile and client requirements. The figure is for early planning.

Is 500 lumens the same as 500 lux?

No. Lumens are the total light output from a light source, while lux is measured at the surface. The same 500-lumen light fixture produces different lux levels across different areas. A light meter records actual illuminance after installation.

Can I calculate lux from a light fitting?

Yes, but the luminaire output must be considered with beam angle, mounting height, spacing and room surfaces. This calculator provides an early target; a photometric layout establishes the fitting quantity and illuminance distribution.

What lux levels are typical for warehouse lighting?

Storage and distribution areas are often planned around 100–300 lux, with higher levels for packing, inspection, loading bays or safety-critical tasks. Racking height and aisle layout can change the final design significantly.