What is the difference between lux and lumens?

Lux measures illuminance (light per unit area), while lumens measure total luminous flux (total light output). Lumens = Lux × Area in square meters.

Lux to Lumen Calculator

Q: How do you convert lux to lumens?

To convert lux to lumens, use the formula: lumens = lux × area (m²). Lux measures illuminance per unit area, so you need the total illuminated area to calculate total luminous flux.

Q: Why do you need area to convert lux to lumens?

Lux is illuminance per square meter, so to find total light output (lumens), you must multiply by the total illuminated area. Larger areas require more lumens to achieve the same lux level.

Convert lux to lumens with step-by-step calculations. Perfect for lighting design, illuminance measurements, and photometric calculations.

Illuminance to Luminous Flux Converter

Lux (lx):

Area (m²):

Room Type:

1 m² (Desk) 9 m² (Small Room) 20 m² (Living Room) 50 m² (Office)

Common Lux to Lumen Conversions

Click on these links to see instant conversions with common values:

Understanding Lux to Lumen Conversion

Converting lux to lumens requires understanding the relationship between illuminance (light per unit area) and luminous flux (total light output). The conversion depends on the total illuminated area.

Conversion Formula

lumens = lux × area (m²)

Where:
• lumens = total luminous flux
• lux = illuminance (light per m²)
• area = illuminated surface area in square meters

Key Concepts

Lux (lx): Illuminance - the amount of light falling on a surface per unit area
Lumens (lm): Luminous flux - the total amount of visible light emitted
Area (m²): The surface area being illuminated
Relationship: To maintain the same lux level, larger areas need more lumens

Recommended Illuminance Levels

Room/Activity	Recommended Lux	Typical Area	Required Lumens
Bedroom	150-300	12 m²	1800-3600 lm
Living Room	200-400	20 m²	4000-8000 lm
Kitchen	300-750	15 m²	4500-11250 lm
Office Work	300-500	10 m²	3000-5000 lm
Reading Area	500-750	1 m²	500-750 lm
Detailed Work	750-1500	1 m²	750-1500 lm

Frequently Asked Questions

How do you convert lux to lumens?

Multiply lux by the illuminated area in square meters. For example: 500 lux × 10 m² = 5000 lumens. You need both illuminance and area to calculate total light output.

Why do you need area to convert lux to lumens?

Lux measures light per unit area (lx = lm/m²), so to find total lumens, you multiply by the total area. Larger spaces need more lumens to achieve the same illuminance.

What's the difference between lux and lumens?

Lux measures illuminance (light falling on a surface per square meter), while lumens measure total light output. Lumens are independent of area, but lux depends on both lumens and area.