Calculate lighting levels for downlights, panels, rooms and more — instantly
Enter the fixture's lumen output, beam angle and the distance to the surface you're lighting.
Calculate the average maintained lux level across a room using the Lumen Method — the industry-standard approach for grid layouts.
Calculate the average lux delivered to a work plane below a panel, batten or linear fixture.
Know the lux level you need to achieve? Work backwards to find the lumens required from your fixture.
Based on AS/NZS 1680 and general industry standards
| Space / Task | Lux (Em) |
|---|---|
| Corridor / passageway | 50 |
| Storage / stairway | 80 |
| Bedroom / lounge | 100–150 |
| Hotel room / dining | 200 |
| General office | 320 |
| Open plan office | 400 |
| Retail / supermarket | 500 |
| Kitchen bench | 750 |
| Drawing / detail work | 1000 |
| Medical / surgical | 1500+ |
UGR = Unified Glare Rating. Lower is better. Based on AS/NZS 1680 & CIE 117.
⚠️ True UGR requires photometric data files from the manufacturer. Our Glare Risk Guide below is a practical indicator based on beam angle, mounting height and lux level.
Lumens = total light output of a source. Lux = lumens landing on one square metre of surface. Same bulb, twice the distance = roughly ¼ the lux (inverse square law).
A spotlight is brightest at the centre of its beam. Centre lux is the peak — useful for displays. Average lux across the beam is more representative of the general light level.
Lighting depreciates over time as lamps dim and dust accumulates. A maintenance factor of 0.8 means designing for 25% more than the minimum needed — so you still meet the target at end-of-life.
Double the distance from a spotlight to a surface and you get roughly one quarter of the lux. This is why mounting height matters so much — a 2.7m vs 3m ceiling can mean a noticeable difference in light levels at desk height.
The industry-standard formula for calculating average room lux: Em = (N × Φ × UF × MF) / A. Where N = number of fixtures, Φ = lumens per fixture, UF = utilisation factor, MF = maintenance factor, A = floor area.
Peak centre lux = Lumens / (2π(1−cos(θ/2)) × d²). Average lux across the beam = Lumens / (π × r²) where r = d × tan(θ/2). Centre lux is typically 1.5–2× higher than the average.
Calculations are an estimate. On-site measurement with a calibrated lux meter is required for compliance reporting (AS/NZS 1680), NCC energy assessments, and lighting commissioning. Good meters start from ~$30.
Lux is the measure of illuminance — how much light falls on a surface. It is the most important metric in practical lighting design because it tells you whether a space will be bright enough for the tasks performed in it. Getting the lux level right means people can see clearly and comfortably without eyestrain or glare.
These two units are often confused but measure very different things. Lumens measure the total light output of a fitting — it's a property of the light source itself. Lux measures how much of that light reaches a surface — it depends on lumens, room size, ceiling height, and how the fitting distributes light.
A 1,000-lumen fitting in a 10m² room and the same fitting in a 100m² room produce very different lux levels — 100 lux and 10 lux respectively. This is why room size is just as important as fitting output.
In Australia, recommended lux levels for different tasks and spaces are specified in AS/NZS 1680. Here are the key values:
| Space / Task | Recommended Lux | AS/NZS 1680 Reference |
|---|---|---|
| Storage, plant rooms | 80–160 lx | AS/NZS 1680.2.4 |
| Corridors, stairways | 160 lx | AS/NZS 1680.1 |
| Retail, general areas | 200–300 lx | AS/NZS 1680.2.5 |
| Office — general | 320 lx | AS/NZS 1680.2.2 |
| Office — desk work | 400–500 lx | AS/NZS 1680.2.2 |
| Classroom | 320–400 lx | AS/NZS 1680.2.3 |
| Workshop / manufacturing | 320–500 lx | AS/NZS 1680.2.4 |
| Healthcare — ward | 200 lx general, 1000 lx examination | AS/NZS 1680.2.5 |
| Retail — feature displays | 500–1000 lx | AS/NZS 1680.2.5 |
| Sports courts (indoor) | 300–750 lx | AS/NZS 1680.2.6 |
The utilisation factor (UF) accounts for the fact that not all light produced by a fitting reaches the working plane. Light is absorbed by walls, ceilings and obstructions, and the geometry of the room affects how efficiently light is distributed. UF values range from about 0.3 (poor — tall narrow room, dark surfaces) to 0.75 (excellent — wide room, white surfaces).
The maintenance factor (MF) accounts for the fact that light output decreases over time due to lamp depreciation and dirt accumulation on fittings and room surfaces. Typical values are:
LED fittings have better lumen maintenance than fluorescent, so a maintenance factor of 0.8 is commonly used for LED installations.
Glare is discomfort or visual impairment caused by excessive brightness contrast in the field of view. It is formally measured by the Unified Glare Rating (UGR). Lower UGR values mean less glare. AS/NZS 1680 specifies maximum UGR limits for different applications:
| Application | Max UGR |
|---|---|
| Drawing offices, fine inspection | 16 |
| General offices, computer work | 19 |
| Retail, reception | 22 |
| Warehouses, general industry | 25 |
| Rough work, heavy industry | 28 |
To control glare in practice: use fittings with deep recessed baffles or prismatic diffusers, avoid bare LED chips visible in the line of sight, and use more, lower-wattage fittings at closer spacing rather than fewer very bright fittings.