Loading...
Convert illuminance units between lux, foot-candles, phot, kilolux, millilux, and nox instantly. Includes common lighting levels reference for photography and design.
Illuminance measures the total luminous flux (visible light) incident on a surface per unit area. The SI unit is lux (lx), equal to one lumen per square meter, commonly used in lighting design, photography, and workplace safety.
| Scenario | Lux | Foot-candles |
|---|---|---|
| Direct Sunlight | 100,000 | ~9,290 |
| Overcast Day | 1,000 | ~93 |
| Office Lighting | 300-500 | 28-46 |
| Living Room | 50-300 | 5-28 |
| Full Moon | 0.25-1 | 0.02-0.09 |
| Starlight | 0.0001 | ~0.00001 |
Key Formulas:
Lux vs Lumens: Lumens measure total light output from a source, while lux measures how concentrated that light is on a surface. The same bulb will produce lower lux readings at greater distances.
Formula
E (lux) = Φ (lumens) ÷ A (m²) | 1 foot-candle = 10.7639 luxE = Illuminance in lux (lx) — luminous flux per unit area
Φ (phi) = Luminous flux in lumens (lm) — total light emitted
A = Area in square metres (m²)
fc = Foot-candle — illuminance from one candela at one foot distance
Worked Example
Convert 500 lux to foot-candles
Did you know? The human eye can adapt to illuminance across 10 orders of magnitude — from 0.001 lux (moonless starry night) to 100,000 lux (direct sunlight). Most office lighting standards recommend 300–500 lux for comfortable desk work.
Sources
Convert between degrees, radians, gradians, turns, and arc units for math and science.
Balance chemical equations by finding the correct coefficients for reactants and products.
Calculate radius, diameter, circumference, area, arc length, and sector area from any input.
Convert between kg/m³, g/cm³, lb/ft³, and more. Includes material density reference.
Differentiate polynomial functions with step-by-step power rule application.
Solve C₁V₁ = C₂V₂ for any missing variable in solution dilution problems.