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Lux lighting measures the light that actually lands on a surface. Lumens measure the light that leaves the fixture. One lux equals one lumen spread over one square metre, so a 10,000 lumen high bay delivers 10,000 lux across one square metre, or 100 lux spread across 100 square metres. Same fixture. Same lumens. Two very different rooms.
That gap is where most quoting mistakes happen.
Here’s the deal. A supplier sells you lumens because lumens are printed on the box. Your inspector, your safety officer and your electrician all care about lux lighting, because lux is what a light meter reads at the work surface. Get those two mixed up and you either over-spend on fixtures you don’t need or fail a lighting measurement on a job you already invoiced.
This guide covers what lux lighting means, how it relates to lumens, the arithmetic that links them, and the lux levels that are legally required in Canadian federally regulated workplaces. Numbers come straight from the regulation, not from a vendor blog.
Lux Lighting vs. Lumens: The Short Answer
| Lumens (lm) | Lux (lx) | |
|---|---|---|
| What it measures | Luminous flux, total light output | Illuminance, light arriving on a surface |
| Where it’s measured | At the source, in a lab sphere | On the floor, desk or wall, on site |
| Changes with distance? | No | Yes, drops fast |
| Changes with room size? | No | Yes |
| Printed on the spec sheet? | Almost always | Almost never |
| What an inspector reads | Nothing | This |
| Formula | Fixed rating | lux = lumens ÷ square metres |
Lumens describe the product. Lux lighting describes the result. You buy the first and you get judged on the second.
What Is Lux Lighting?
Lux lighting is illuminance measured in lux, the SI unit for how much luminous flux falls on a given area. One lux is one lumen per square metre. The symbol is lx.
Think of a watering can. The litres in the can are your lumens, a fixed quantity. Lux is how wet any single square metre of garden gets. Tip the whole can on one plant and that patch is soaked. Sprinkle it across the lawn and everything is barely damp. You never added or removed water.
Some rough lux lighting benchmarks, so the numbers mean something:
- Direct summer sun: roughly 30,000 to 100,000 lx
- Overcast daylight: roughly 1,000 to 5,000 lx
- Well-lit office: 300 to 500 lx
- Warehouse aisle: 100 to 200 lx
- Covered parking: 50 lx
- Twilight: around 10 lx
- Full moon: well under 1 lx
Notice how compressed the indoor end is. A 500 lx office feels bright to us and it’s roughly one two-hundredth of a sunny afternoon. Human eyes are wildly adaptive, which is exactly why you can’t eyeball a lux lighting level and why arguments on site get settled with a meter, not an opinion.
Lux Lighting, Candela and the SI Family Tree
All three photometric units are related, and the order matters.
- Candela (cd) is luminous intensity in one direction. It’s the SI base unit, realised in Canada by the National Research Council’s photometry group.
- Lumen (lm) is candela multiplied by the solid angle the light covers. Total output.
- Lux (lx) is lumens divided by the area they land on. The result.
So candela is direction, lumen is quantity, lux is delivery. A narrow 15 degree spot and a 120 degree flood can share an identical lumen rating and produce completely different lux lighting on the same floor. The spot concentrates, the flood spreads.
How a Lux Lighting Reading Is Actually Taken
This part gets skipped and it causes real disputes. Under Canada’s federal regulation, an average lux lighting level isn’t one reading. Section 6.3 of the Canada Occupational Health and Safety Regulations requires four measurements at places representative of the area, taken 1 m above the floor, then divided by four.
One reading under the brightest fixture proves nothing. Four readings, one metre up, averaged. That’s the method.
What Is a Lumen?
A lumen is luminous flux, the total visible light a source emits in every direction, weighted for how sensitive the human eye is to each wavelength. It’s measured in a lab, usually in an integrating sphere, and it does not care about your building.
Move a 5,000 lumen fixture from 3 m to 6 m and it still emits 5,000 lumens. The lux on the floor underneath, though, has just collapsed by roughly 75%.
That’s the whole confusion in one sentence.
Lumens are still useful. They’re how you compare products, how you calculate efficacy in lumens per watt, and how you size a retrofit. Our room-by-room and commercial lumen guide works through those targets in detail, so this page stays on the units themselves.
The One Formula That Connects Lux Lighting and Lumens
Two equations do most of the work.
Lumens to lux:
lux = lumens ÷ area in square metres
Lux to lumens:
lumens = lux × area in square metres
That’s it. No conversion factor, no fudge. Lux and lumens are the same quantity, just one divided by an area.
A Worked Lux Lighting Example
Take a 12 m by 8 m machine shop. Floor area is 96 m². Canada’s Schedule II sets 500 lx for medium or fine bench and machine work.
- Required lumens on the floor: 500 lx × 96 m² = 48,000 lumens
- Using 15,000 lumen linear high bay fixtures: 48,000 ÷ 15,000 = 3.2 fixtures
Now the correction almost everyone forgets. Not all of those lumens reach the work surface. Some hit walls, some get absorbed, some are lost as the LEDs age and the lenses collect dust. Apply a light loss factor. For a clean commercial interior 0.8 is reasonable, and for a dusty shop 0.7 is safer.
- Adjusted: 48,000 ÷ 0.7 = 68,600 lumens, or 4.6 fixtures
Round to 5, then lay them out on a grid. Four fixtures would have hit the arithmetic and failed the room. That single 0.7 is the difference between a design that passes and one that gets re-quoted at your cost. Our high bay lighting calculator runs this maths with mounting height built in.
Why Lux Lighting Falls Off So Fast
Point sources obey the inverse square law:
lux = candela ÷ distance in metres²
Double the distance, quarter the lux. Triple it, and you’re at one ninth.
A 20 ft warehouse ceiling isn’t twice the challenge of a 10 ft office ceiling. It’s about four times. That’s why UFO high bays exist with tight optics instead of vendors just selling bigger troffers, and why swapping metal halide for LED high bays usually means rethinking beam angle, not only wattage.
Real rooms aren’t pure point sources. Light bounces off walls and ceilings, so bright finishes lift your lux lighting for free and a matte black warehouse ceiling quietly steals it. Directionally, though, the inverse square law is the rule you plan around.
Lux Lighting vs. Foot-Candles: The Canadian Unit Problem
Canada writes its lux lighting requirements in lux. A lot of the product data and design software crossing the border is in foot-candles. So both sit on the same drawing set, which is fun for nobody.
A foot-candle is one lumen per square foot. One square foot is 0.0929 m², so:
- 1 foot-candle = 10.764 lux
- 1 lux = 0.0929 foot-candles
For field maths, 1 fc is about 10 lx. Close enough to sanity-check a number in your head, and about 7% low, so don’t hand it to an inspector.
| Foot-candles | Lux | Typical space |
|---|---|---|
| 1 fc | 10.8 lx | Open parking, low-activity exterior |
| 5 fc | 53.8 lx | Covered parking, storage |
| 10 fc | 107.6 lx | Warehouse aisle, corridor |
| 20 fc | 215.3 lx | Bulk storage, boiler room |
| 30 fc | 322.9 lx | Reception, conference room |
| 50 fc | 538.2 lx | Office desk work, food prep |
| 75 fc | 807.3 lx | Laboratory instrument reading |
| 100 fc | 1,076.4 lx | Drafting, first aid treatment |
Honestly, this table settles more arguments than any other part of a spec conversation. When a US datasheet promises 50 fc and the Canadian spec says 500 lx, they’re within 8% of each other and everybody can go home.
Canadian Lux Lighting Levels That Are Actually Law
Most lux lighting articles quote generic international recommendations. Canada has binding numbers, and they’re free to read. Part VI of the Canada Occupational Health and Safety Regulations sets minimum lux levels for federally regulated workplaces, current to 2026-06-21 and last amended on 2025-03-26.
One qualifier before the tables. These apply to federally regulated employers: banks, telecom, rail, air, marine, interprovincial trucking, the federal public service and Crown corporations. A provincially regulated warehouse in Ontario or BC answers to provincial OHS rules instead. The values still make an excellent design baseline anywhere in Canada, because provincial codes tend to land in the same range.
Office Areas, Schedule I
| Task position or area | Minimum lux |
|---|---|
| Cartography, designing, drafting, plan-reading | 1,000 lx |
| Typing, filing, accounting, billing, continuous reading or writing | 500 lx |
| Conference and interview rooms, file storage, reception, switchboard | 300 lx |
| Stairways and corridors used frequently | 100 lx |
| Stairways and corridors used infrequently | 50 lx |
| Stairways used only in emergencies | 30 lx |
That 500 lx line is the one you’ll meet most often. It’s the reason a 2×4 LED troffer in the 4,000 to 5,000 lumen band became the default office fixture in Canada, and why replacing fluorescent ceiling panels is usually a like-for-like lumen swap rather than a redesign.
Industrial Areas, Schedule II
| Area | Minimum lux |
|---|---|
| Laboratory instrument reading where errors are hazardous | 750 lx |
| Medium or fine bench and machine work | 500 lx |
| Handling hazardous substances, main work area | 500 lx |
| Major control rooms, dial displays | 500 lx |
| Rough bench or machine work | 300 lx |
| Garage main repair and maintenance | 300 lx |
| Packages frequently checked or sorted | 250 lx |
| Loading docks, piers, container handling | 150 lx |
| Fuelling areas | 150 lx |
| Battery rooms | 100 lx |
| Main corridor and aisle intersections | 100 lx |
| Goods in storage of different kinds | 75 lx |
| Bulk storage, single-kind goods | 30 lx |
| Bulk grain or granular loading | 30 lx |
| Any other storage or warehouse area | 10 lx |
Look at the spread. Bulk storage at 30 lx and a sorting bench at 250 lx sit in the same building, often under the same roofline. One uniform grid of linear fixtures for warehouses either wastes energy over the racking or starves the pick face. Zoning is cheaper than over-lighting.
General and Exterior Areas, Schedule III
| Area | Minimum lux |
|---|---|
| First aid treatment and examination area | 1,000 lx |
| First aid, other areas | 500 lx |
| Food preparation areas | 500 lx |
| Personal service rooms | 200 lx |
| Boiler rooms | 200 lx |
| Lobbies and atria | 100 lx |
| Exterior entrances and exits used frequently | 100 lx |
| Exterior entrances and exits used infrequently | 50 lx |
| Covered parking | 50 lx |
| HVAC equipment rooms | 50 lx |
| Emergency shower and equipment locations | 50 lx |
| Exterior passageways at vehicular intersections | 30 lx |
| Exterior storage, high or moderate activity | 30 lx |
| Areas with persons and mobile equipment, high or moderate activity | 20 lx |
| Open parking | 10 lx |
| Exterior passageways, other locations | 10 lx |
Open parking at 10 lx surprises people who’ve been sold 30 lx lots. If you’re laying out a site, our commercial outdoor area lighting spec guide pairs these floors with pole spacing and photometrics for LED area lights.
Screen Work, Schedule IV, and the Rule That Runs Backwards
Here’s a detail almost nobody quotes correctly. Schedule IV is a maximum, not a minimum. Section 6.7(1) says the average level at these positions “shall not be more than” the listed value, because too much ambient light washes out a display and creates reflection glare.
| VDT task position | Maximum lux |
|---|---|
| Data entry and retrieval performed intermittently | 500 lx |
| Data entry performed exclusively | 750 lx |
| Telephone operator areas | 300 lx |
And section 6.7(3) adds a floor on top: when screen work involves reading a paper document, supplementary lighting must give at least 500 lx on that document. Ambient capped, task light required. Get that backwards on a call centre spec and you’ve designed the wrong building.
The One-Third Lux Lighting Uniformity Rule
Section 6.11(1) is the sleeper clause. No single measurable point may fall below one third of the prescribed level for that area.
So a 500 lx office can’t dip below about 167 lx anywhere. A 300 lx garage bay can’t drop under 100 lx in the corners.
This is precisely the requirement a lumen number cannot answer. Two layouts, identical total lumens, identical average lux lighting, and one passes while the other fails because the fixtures are spaced too far apart and the floor scallops between them. Uniformity is a spacing and beam-angle problem, and it’s why photometric files matter more than nameplate lumens on any job that gets measured.
Emergency lighting has its own pair of numbers. Section 6.10(2)(b) requires an average of at least 10 lx, and for buildings begun after 1990-10-31, section 6.11(4) says no point may read below 0.25 lx. If you’re specifying emergency lights and exit signage, those are the two figures that matter, and our emergency lighting and backup systems guide walks through battery duration alongside them.
Lux Lighting vs. Nits, Candela and Watts
Four more units get tangled into lux lighting conversations. Quick sort:
- Candela (cd) measures intensity in one direction. Used for spotlights, beam angles and photometric files. Feeds the inverse square law.
- Nits (cd/m²) measure luminance, how bright a surface looks to an eye or camera. Screens and signage, not floors. A monitor’s 400 nit rating tells you nothing about your lux lighting.
- Watts (W) measure electricity consumed. Watts stopped predicting brightness the moment LEDs arrived.
- Lumens per watt (lm/W) measure efficacy, output per unit of power. This is the number that drives energy bills and rebate eligibility.
Efficacy is where lux lighting and money meet. Two fixtures that both deliver 500 lx on your floor can differ 40% in draw. That difference is the whole basis of DLC certification and most Canadian utility incentive programmes, so it’s worth checking before a commercial retrofit goes to order.
How to Spec Fixtures From a Lux Lighting Target
Five steps. Follow them in order.
- Find your required lux lighting level, don’t guess it. Pull it from the schedules above or your provincial OHS equivalent. Write the section number on the drawing.
- Measure the real area in square metres. Task areas, not gross floor plate. A 400 m² warehouse with 300 m² of racking has 100 m² that needs pick-face light.
- Multiply for raw lumens. Target lux × area. That’s your delivered requirement.
- Divide by a light loss factor. 0.8 clean interior, 0.7 dusty or high-ceiling, 0.6 harsh industrial. This accounts for lumen depreciation, dirt and absorption.
- Check uniformity, not just the average. Confirm no point drops under a third of target. Mounting height, beam angle and spacing decide this, and only a photometric layout proves it.
Two extras that change your lux lighting answer. Colour temperature doesn’t alter lux, but 4000K reads as crisper than 3000K at identical illuminance, which our colour temperature guide covers. And surface reflectance is free light. White walls and a light ceiling can add 10 to 20% to your working lux lighting compared with dark finishes. Same fixtures, same power.
Where Lumen Ratings Mislead Buyers
Five traps worth knowing.
- Chip lumens instead of fixture lumens. Raw LED output before the lens, diffuser and driver losses. Delivered light can be 20 to 30% lower. Always ask for tested fixture lumens.
- Initial lumens with no L70 figure. LEDs fade. A fixture at exactly your target on day one is under it by year six. Design to maintained output.
- Lumens with no beam angle. 10,000 lumens at 60 degrees and at 120 degrees light entirely different floors. Lumens without optics is half a spec.
- Ignoring mounting height. The single biggest lux lighting killer. Inverse square law does not negotiate.
- Averaging away a failure. A room can hit its average lux lighting and still breach the one-third rule between fixtures. Averages hide the dark spots that get flagged.
How to Measure Lux Lighting On Site
You’ll want a lux meter, sometimes sold as a light meter or illuminance meter. Phone apps are fine for a rough sniff and useless for anything you’ll sign. Their sensors aren’t cosine-corrected or properly colour-weighted, and readings drift badly under LED sources.
Basic lux lighting method:
- Hold the sensor flat and horizontal at the height that matters. 1 m above the floor for area readings under the federal method, or at the actual work surface for task readings.
- Take four readings at representative spots and average them. That’s the regulated procedure in section 6.3.
- Then hunt the worst spot deliberately, usually midway between fixtures or in a corner, to test the one-third rule.
- Kill daylight. Measure after dark or with blinds closed, otherwise you’re recording the sun.
- Let the fixtures stabilise. LEDs settle within minutes, but older HID needs a full warm-up.
- Log the date, the meter model and the mounting heights. If you ever get challenged, the log is your defence.
The Canadian Centre for Occupational Health and Safety publishes a practical lighting survey walkthrough covering glare and contrast alongside raw illuminance, and it’s worth a read before your first survey.
Frequently Asked Questions
Is 5,000 lux the same as 5,000 lumens?
No. They’re the same only across exactly one square metre. 5,000 lumens spread over 5 m² gives 1,000 lux, and the same 5,000 lumens over 50 m² gives just 100 lux. The lumen figure is fixed by the fixture; the lux figure depends entirely on how far the light spreads and how far away it is.
How many lux is 2,000 lumens?
It depends on the area, so there’s no single answer. 2,000 lumens landing on 1 m² is 2,000 lux, on 10 m² it’s 200 lux, and on 20 m² it’s 100 lux. Divide lumens by the area in square metres. For a real fixture, reduce the result by a light loss factor of 0.7 to 0.8 before trusting it.
Can you convert lux to lumens?
Yes, if you know the illuminated area. Multiply lux by square metres. A 300 lx target across a 40 m² room needs 12,000 lumens on the floor, or roughly 15,000 to 17,000 fixture lumens once losses are covered. Without an area figure, no conversion is possible, which is why online lux-to-lumen calculators always ask for a distance or beam angle first.
How bright is 100 lux?
Dim by working standards. 100 lux suits a warehouse aisle, a building lobby or a frequently used exterior entrance, and it’s Canada’s minimum for a main corridor intersection in an industrial area. It’s about a fifth of what a desk needs for reading and writing. You can move safely at 100 lux but you wouldn’t want to do detailed work there.
How much lux is good for your eyes?
For reading, writing and screen work, 300 to 500 lux at the work surface is the accepted comfort range, and Canada’s federal regulation requires 500 lux for continuous reading or writing. Detailed tasks like drafting want 1,000 lux. Eye strain usually comes from glare, flicker and contrast rather than from the lux lighting level itself, so a well-diffused 400 lux beats a harsh 700 lux every time.
Bottom Line
- Lumens leave the fixture. Lux arrives on the surface. One lux is one lumen per square metre.
- lux = lumens ÷ square metres. Rearrange it in either direction; there’s no conversion constant.
- Always divide by a light loss factor of 0.7 to 0.8. Skipping it is the most common under-spec in the trade.
- Distance dominates. Inverse square law means doubling mounting height quarters your lux lighting.
- Lux lighting is a layout problem, not a purchase. Beam angle, mounting height and spacing decide it, so photometric files beat nameplate lumens.
- 1 fc = 10.764 lx. Keeps Canadian specs and US datasheets talking to each other.
- Averages aren’t enough. Canada’s one-third uniformity rule fails layouts that pass on paper.
Working from a lux lighting target instead of a lumen guess is what separates a lighting design that gets signed off from one that gets re-done. If you’re pricing a project and want the photometric files to back the numbers, browse the full LED fixture range or send your floor area and target lux to the Votatec team for a wholesale quote.
