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.