The conversion of 40 lux to lumens depends on the surface area over which the light is spread. Assuming a 1 square meter area, 40 lux equals 40 lumens. This is because lumens measure total light output, while lux measures light intensity per square meter.
Lux and lumens are related but different units; lux indicates how bright a surface is illuminated, lumens indicate the total light emitted. To convert lux to lumens, multiply lux by the area in square meters that receives the light.
Conversion Tool
Result in lumens:
Conversion Formula
The formula to convert lux (lx) to lumens (lm) is:
Lumens = Lux × Area (in square meters)
This formula works because lux measures the illuminance on a surface, which is lumens per square meter. So, to find total lumens, you multiply the lux level by the size of the lit area.
For example, if a surface of 2 square meters receives 40 lux of light, then the lumens is calculated as:
- Lux = 40 lx
- Area = 2 m²
- Lumens = 40 × 2 = 80 lm
Conversion Example
- Example 1: 25 lux to lumens
- Assume area = 1.5 m²
- Lumens = 25 × 1.5 = 37.5 lm
- Multiply lux value by the area, so 25 lux on 1.5 m² equals 37.5 lumens.
- Example 2: 50 lux to lumens
- Area = 3 m²
- Lumens = 50 × 3 = 150 lm
- The total light output on 3 square meters is 150 lumens.
- Example 3: 10 lux to lumens
- Area = 4 m²
- Lumens = 10 × 4 = 40 lm
- 10 lux over 4 square meters equals 40 lumens in total.
- Example 4: 60 lux to lumens
- Area = 0.5 m²
- Lumens = 60 × 0.5 = 30 lm
- Multiplying lux by area gives total lumens, so 60 lux on half a square meter equals 30 lumens.
Conversion Chart
| Lux (lx) | Lumens (lm) (Area = 1 m²) |
|---|---|
| 15.0 | 15.0 |
| 20.0 | 20.0 |
| 25.0 | 25.0 |
| 30.0 | 30.0 |
| 35.0 | 35.0 |
| 40.0 | 40.0 |
| 45.0 | 45.0 |
| 50.0 | 50.0 |
| 55.0 | 55.0 |
| 60.0 | 60.0 |
| 65.0 | 65.0 |
This chart shows lux values converted to lumens assuming an area of 1 square meter. To use it for other sizes, multiply the lumens value by the area in square meters.
Related Conversion Questions
- How many lumens are in 40 lux on a 2 square meter surface?
- What is the lumen output when 40 lux is spread over 0.5 square meters?
- Can 40 lux be converted to lumens without knowing the area?
- What area does 40 lux cover if the total lumens are 80?
- Is 40 lux enough to produce 100 lumens on a surface?
- How to convert 40 lux to lumens in a room measuring 10 square meters?
- Does 40 lux mean the same as 40 lumens for a 1 m² space?
Conversion Definitions
Lux: Lux is a unit that measures illuminance, which means how much light falls on a surface area. One lux equals one lumen per square meter, indicating light intensity perceived by the human eye on a specific area.
Lumens: Lumens measure the total amount of visible light emitted by a source. It quantifies brightness as perceived by the human eye, regardless of the area that light covers, unlike lux which depends on surface size.
Conversion FAQs
Why do I need to know the surface area to convert lux to lumens?
Because lux measures light per unit area, without knowing how many square meters the light covers, you can’t calculate total lumens. Lumens represent total light output, so you multiply lux by area to get lumens.
Can I convert lux to lumens if I don’t know the area?
No, it’s impossible to accurately convert lux to lumens without the area because lux depends on how spread out the light is. Without area, lumens calculation lacks the necessary factor to determine total light.
Does 40 lux always equal 40 lumens?
Only if the illuminated surface is exactly 1 square meter. If the area is larger or smaller, then the lumens value changes proportionally, since lumens = lux × area.
Is the conversion affected by the angle of light?
Indirectly, yes. The angle affects how light spreads on a surface which changes the effective area and thus the lux level. This changes the total lumens when calculated using the formula.
How does light source efficiency affect lux and lumens?
Light source efficiency influences lumens, as it defines how much visible light is emitted. Lux is dependent on how that light spreads on surfaces, so efficiency impacts lumens directly, but lux depends on environment and distance.