Lumen to Lux Calculator – Illuminance Converter
Convert lumens to lux based on area and calculate illuminance
Table of Contents
How to Use
- Enter the total lumens of your light source
- Enter the area to be illuminated
- Select your area unit (square meters or square feet)
- Click calculate to see the illuminance in lux
What is Lux?
Lux (lx) is the SI unit of illuminance, measuring the amount of light that falls on a surface. One lux equals one lumen per square meter (lm/m²). It describes how bright a surface appears based on the light it receives.
Unlike lumens, which measure total light output, lux measures light intensity at a specific location. The same light source will produce different lux values depending on the distance and area it illuminates.
Lumens vs Lux
Understanding the difference between lumens and lux:
- Lumens (lm): Total amount of visible light emitted by a source
- Lux (lx): Amount of light falling on a surface per unit area
- Formula: Lux = Lumens / Area (in square meters)
- 1 lux = 1 lumen per square meter
- 1 foot-candle = 1 lumen per square foot ≈ 10.764 lux
Recommended Illuminance Levels
Typical lux requirements for different environments:
| Environment | Recommended Lux | Purpose |
|---|---|---|
| Moonlight | 0.1-1 lx | Natural night vision |
| Street Lighting | 5-20 lx | Safe pedestrian movement |
| Living Room | 50-150 lx | General activities |
| Office Work | 300-500 lx | Computer work, reading |
| Detailed Work | 500-1000 lx | Technical drawing, inspection |
| Precision Tasks | 1000-2000 lx | Surgery, fine assembly |
| Direct Sunlight | 32,000-100,000 lx | Outdoor daylight |
Lighting Design Applications
Lux calculations are essential for:
- Architectural lighting design
- Workplace safety and compliance
- Photography and videography setup
- Retail and display lighting
- Sports facility illumination
- Road and street lighting design
- Museum and gallery lighting
- Energy-efficient lighting planning
Frequently Asked Questions
- What is the difference between lumens and lux?
- Lumens measure the total light output from a source, while lux measures how much light falls on a surface. The same number of lumens spread over a larger area results in lower lux values.
- How many lux do I need for reading?
- For comfortable reading, 300-500 lux is recommended. For detailed reading or for older adults, 500-750 lux or higher may be more comfortable.
- How do I increase lux without changing bulbs?
- You can increase lux by: moving lights closer to the surface, using reflective surfaces to bounce light, adding more light fixtures, or reducing the area you're trying to illuminate.
- What is a foot-candle and how does it relate to lux?
- A foot-candle (fc) is the imperial unit of illuminance, equal to one lumen per square foot. One foot-candle equals approximately 10.764 lux. It's commonly used in North America for lighting specifications.