Illuminance Converter
Convert between lux, foot-candles, phot, and more
Conversion Formula:
Multiply by 0.09290313
Common Conversions
Illuminance Comparison Chart
| Lighting Condition | Lux (lx) | Foot-candles (fc) | Application |
|---|---|---|---|
| Starlight | 0.0001 - 0.001 | 0.00001 - 0.0001 | Night vision threshold |
| Full Moon | 0.1 - 0.3 | 0.01 - 0.03 | Night outdoor visibility |
| Deep Twilight | 1 - 10 | 0.1 - 1 | Emergency lighting |
| Living Room | 50 - 200 | 5 - 20 | Residential lighting |
| Office | 300 - 500 | 30 - 50 | Task lighting, workspaces |
| Overcast Day | 1,000 - 5,000 | 100 - 500 | Outdoor photography |
| Operating Room | 10,000 - 20,000 | 1,000 - 2,000 | Medical procedures |
| Direct Sunlight | 32,000 - 100,000 | 3,000 - 10,000 | Maximum natural light |
Understanding Illuminance
What is Illuminance?
Illuminance is the measure of how much luminous flux (light) is spread over a given area. It essentially measures the amount of light falling onto a surface. The standard SI unit is lux (lx), which equals one lumen per square meter.
Key Units:
- Lux (lx): The SI unit, equal to one lumen per square meter
- Foot-candle (fc): US customary unit, equal to one lumen per square foot (1 fc approx 10.764 lux)
- Phot (ph): CGS unit, equal to one lumen per square centimeter (1 phot = 10,000 lux)
- Nox/Millilux (nx/mlx): Used for very low light levels (1 nox = 0.001 lux)
Applications:
- Architectural Lighting: Design of interior and exterior lighting for buildings
- Photography: Determining proper exposure settings
- Safety Regulations: Ensuring minimum light levels in workplaces
- Energy Efficiency: Optimizing light levels to reduce energy consumption
- Horticulture: Measuring light for plant growth
- Display Technology: Screen brightness and readability
Measurement Tools:
Illuminance is measured using a light meter (lux meter or illuminance meter), which contains a photocell that converts light energy to electrical current.
Recommended Illuminance Levels
| Space Type | Recommended (lux) | Recommended (fc) |
|---|---|---|
| Corridors, hallways | 100 | 10 |
| Stairways | 150 | 15 |
| Conference rooms | 300-500 | 30-50 |
| General office work | 500 | 50 |
| Mechanical workshops | 500-750 | 50-75 |
| Electronic assembly | 1,000-1,500 | 100-150 |
| Detailed drawing work | 750-1,000 | 75-100 |
| Quality control | 1,000-1,500 | 100-150 |
These values are based on recommended standards from organizations like the Illuminating Engineering Society (IES) and various international standards. Actual requirements may vary by country and local building codes.
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Visual Comparison
500 lux
≈ 500 lux
Description: Overcast day, indirect daylight
Similar Environments:
Human Vision at this Level:
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About the Illuminance Converter
Convert between lux, foot-candles, phot, and more All conversions run instantly in your browser and nothing you enter is sent to a server.
Common Conversion Formulas
| From | To | Formula |
|---|---|---|
| Lux (lx) | Foot-candle (fc) | fc = lx × 0.092903 |
| Lux (lx) | Phot (ph) | ph = lx × 0.0001 |
| Candela (cd) at distance (d meters) | Lux (lx) | lx = cd / d² |