Convert illuminance units — lux, foot-candle, phot, nox and more.
| Unit | Name | Value |
|---|---|---|
| lx | Lux | 0.001 |
| fc | Foot-candle | 0.00009290313 |
| ph | Phot | 1e-7 |
| nx | Nox | 1 |
| klx | Kilolux | 0.000001 |
Formula: Lux = Millilux × 0.001
Multiply any Millilux value by 0.001 to get Lux.
Reverse: Millilux = Lux × 1000
Common illuminance levels — factor: 1 mlx = 0.001 lx
| Millilux (mlx) | Lux (lx) | Context |
|---|---|---|
| 0.1 mlx | 0.0001 lx | Moonless overcast |
| 1 mlx | 0.001 lx | Dark countryside |
| 10 mlx | 0.01 lx | Moonlit night |
| 100 mlx | 0.1 lx | Full moon |
| 1000 mlx | 1 lx | 1 lx — full moon bright |
| 1e+04 mlx | 10 lx | 10 lx — candle |
| 1e+05 mlx | 100 lx | 100 lx — corridor |
| 5e+05 mlx | 500 lx | 500 lx office |
| 1e+06 mlx | 1000 lx | 1,000 lx studio |
| 5e+06 mlx | 5000 lx | 5,000 lx overcast |
| 1e+07 mlx | 1e+04 lx | 10 klx SAD lamp |
| 5e+07 mlx | 5e+04 lx | 50 klx hazy sun |
| 1e+08 mlx | 1e+05 lx | 100 klx bright sun |
| 1.000e+09 mlx | 1e+06 lx | Very bright |
| 1.300e+11 mlx | 1.3e+08 lx | Tropical sun |
mlx ÷ 1,000 = lx.
1,000 mlx = 1 lx. 1 mlx = 0.001 lx (dark sky).
lx × 1,000 = mlx.
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.
Millilux (mlx) equals 0.001 lux and is used for measuring very low light levels in astronomical, military, and low-light imaging applications. Starlight provides about 0.001–0.01 lx (1–10 mlx); a quarter moon about 0.1 lx (100 mlx).
Night vision equipment, wildlife cameras, and low-light sensor testing use millilux. Military specification MIL-STD-1783 specifies cockpit illumination in millilux for night-vision-compatible conditions. Astronomical photometry measures sky background in millilux.
Interesting fact: The minimum illuminance for the human eye to detect is approximately 0.0001 mlx (0.1 μlx), achieved only in the darkest conditions with fully dark-adapted eyes. Rod photoreceptors, responsible for night vision, are about 1,000 times more sensitive than cones.
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).
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 mlx = 0.001 lx. Reverse: 1 lx = 1000 mlx.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.