Convert illuminance units — lux, foot-candle, phot, nox and more.
| Unit | Name | Value |
|---|---|---|
| fc | Foot-candle | 0.09290313 |
| ph | Phot | 0.0001 |
| nx | Nox | 1000 |
| klx | Kilolux | 0.001 |
| mlx | Millilux | 1000 |
Formula: Kilolux = Lux × 0.001
Multiply any Lux value by 0.001 to get Kilolux.
Reverse: Lux = Kilolux × 1000
Common illuminance levels — factor: 1 lx = 0.001 klx
| Lux (lx) | Kilolux (klx) | Context |
|---|---|---|
| 0.001 lx | 1.000e-06 klx | Moonless overcast night |
| 0.01 lx | 1.000e-05 klx | Dark countryside sky |
| 0.1 lx | 0.0001 klx | Moonlit night |
| 1 lx | 0.001 klx | Full moon |
| 10 lx | 0.01 klx | Candle at 1 m |
| 50 lx | 0.05 klx | Living room typical |
| 100 lx | 0.1 klx | Corridor / stairway |
| 300 lx | 0.3 klx | Classroom |
| 500 lx | 0.5 klx | Office work / IES standard |
| 1000 lx | 1 klx | Studio lighting |
| 5000 lx | 5 klx | Bright overcast day |
| 1e+04 lx | 10 klx | SAD therapy lamp |
| 2.5e+04 lx | 25 klx | Overcast daylight |
| 1e+05 lx | 100 klx | Bright sunlight |
| 1.3e+05 lx | 130 klx | Tropical noon sun |
lx ÷ 1,000 = klx. Shift decimal 3 left.
1,000 lx = 1 klx. 10,000 lx = 10 klx (SAD therapy). 100,000 lx = 100 klx.
klx × 1,000 = lx.
Specifies illuminance levels in lux (metric) or foot-candles (US) for architectural, retail, and workplace lighting per IES and EN 12464 standards.
Measures scene illuminance in lux with a light meter to set correct exposure for available-light photography.
Verifies that workplace lighting meets minimum requirements (typically 500 lx for offices, 300 lx for corridors) per local regulations.
Monitors grow-light illuminance in klx to optimize plant growth — fruiting plants typically need 20–60 klx.
Prescribes and measures light therapy intensity in lux for SAD treatment (10,000 lx standard) and circadian rhythm research.
Measures ambient light in lux to set appropriate display backlight levels for consistent image quality.
The lux (lx) is the SI unit of illuminance, defined as one lumen per square meter. It measures how much light falls on a surface, regardless of the surface's color or reflectivity. The lux was formally adopted by the International System of Units in 1960, superseding the older phot and metre-candle.
Lux levels define lighting requirements across all domains: emergency lighting minimum 1 lx, corridor lighting 100 lx, office work 500 lx, surgery 10,000–100,000 lx. Outdoor daylight ranges from 1,000 lx (overcast) to 130,000 lx (direct tropical sunlight).
Interesting fact: Human eyes can adapt to a remarkable range — from about 0.001 lx (moonless night) to over 130,000 lx (direct sunlight) — a factor of 100 million. Yet the lighting standards for reading (500 lx) are only 500 times brighter than a typical moonlit night (1 lx).
Kilolux (klx) equals 1,000 lux and is used for high-illuminance environments including daylight simulation, horticulture, and phototherapy. Direct sunlight registers 80–130 klx; overcast daylight 1–25 klx.
Seasonal affective disorder (SAD) treatment lamps provide 10 klx at close range for 30-minute daily sessions. Horticulture lighting for fruiting plants targets 20–60 klx. Industrial quality control inspection stations may require 5–10 klx.
Interesting fact: The human circadian rhythm is most strongly reset by 10 klx blue-enriched light in the morning. Even 2.5 klx has measurable circadian effects — explaining why indoor living (typically 200–500 lx) can disrupt sleep cycles.
Illuminance measures light falling on a surface. The SI unit is lux (lm/m²); the US standard is foot-candles (lm/ft²). Key reference levels: moonless night ~0.001 lx, full moon ~1 lx, office work 500 lx, SAD therapy 10,000 lx, bright sunlight 100,000 lx.
Exact factor: 1 lx = 0.001 klx. Reverse: 1 klx = 1000 lx.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.