100 lux corresponds to 100 lumens if the illuminated surface area is exactly 1 square meter. Lux measures illuminance (lumens per square meter), so 100 lux means 100 lumens spread evenly over 1 m².
Lux is a measure of how much light hits a surface, while lumens measure total light output. To convert lux to lumens, you multiply the lux value by the surface area in square meters where the light is distributed.
Conversion Tool
Result in lumens:
Conversion Formula
The formula to convert lux to lumens is:
Lumens = Lux × Area (in square meters)
Because lux measures luminous flux per square meter, to find total lumens you multiply the lux value by the total surface area illuminated.
For example, if you have 100 lux illuminating 1 m², then
- Lumens = 100 lux × 1 m² = 100 lumens
If the area was 2 m², then lumens would be 100 × 2 = 200 lumens.
Conversion Example
- Converting 50 lux on 2 m²:
- Multiply 50 lux by 2 m².
- 50 × 2 = 100 lumens total.
- This means 100 lumens are spread over 2 square meters, resulting in 50 lux illuminance.
- Converting 200 lux on 0.5 m²:
- Multiply 200 lux by 0.5 m².
- 200 × 0.5 = 100 lumens total.
- Here 100 lumens illuminate half a square meter, causing 200 lux level.
- Converting 120 lux on 1.5 m²:
- Multiply 120 lux by 1.5 m².
- 120 × 1.5 = 180 lumens total.
- The total luminous flux is 180 lumens over 1.5 square meters.
Conversion Chart
| Lux (lx) | Lumens (lm) [Area = 1 m²] |
|---|---|
| 75.0 | 75.0 |
| 80.0 | 80.0 |
| 85.0 | 85.0 |
| 90.0 | 90.0 |
| 95.0 | 95.0 |
| 100.0 | 100.0 |
| 105.0 | 105.0 |
| 110.0 | 110.0 |
| 115.0 | 115.0 |
| 120.0 | 120.0 |
| 125.0 | 125.0 |
The chart shows lux values converted to lumens assuming the light is spread evenly over a 1 square meter surface. You can use it to quickly estimate lumens from lux where area is fixed.
Related Conversion Questions
- How many lumens are equal to 100 lux on a 2 square meter surface?
- What is the formula to convert 100 lux into lumens?
- If I have 100 lux lighting, how to calculate total lumens for a room?
- Does 100 lux always equal 100 lumens?
- How does surface area affect converting 100 lux to lumens?
- What is the lumen output of a lamp producing 100 lux on 1 square meter?
- Can 100 lux be converted directly into lumens without area?
Conversion Definitions
Lux: Lux is a photometric unit measuring illuminance, that is the amount of luminous flux received per unit area. It equals one lumen per square meter, describing how brightly light shines on a surface. Lux accounts for human eye sensitivity to light intensity.
Lumens: Lumens measure total luminous flux emitted by a light source in all directions. It quantifies the perceived power of light, showing how much visible light is produced. Lumens do not consider area, only the total light output from the source.
Conversion FAQs
Why can’t I convert lux to lumens without knowing the area?
Lux measures illuminance, which depends on how much light hits a certain area. Without knowing the surface size, you cannot find total lumens because lumens equal lux multiplied by the area. Without area, the conversion is incomplete.
Is 100 lux always equal to 100 lumens?
Not necessarily. 100 lux means 100 lumens per square meter. If the area differs from 1 m², lumens change accordingly. For example, 100 lux on 2 m² equals 200 lumens total.
How does the shape or angle of the surface affect lux to lumens conversion?
The formula assumes flat, perpendicular surfaces. If the surface is angled or curved, the effective area illuminated changes, affecting lux. Therefore, lumens calculated might not match real-world measurements unless geometry is accounted.
Can lux values exceed lumens?
No, because lux depends on lumens spread over an area. High lux means light concentrated in small area, resulting in fewer lumens needed. Lumens represent total light emitted, so they can’t be less than lux multiplied by the area.
Does the color temperature affect lux to lumens conversion?
No, lux and lumens are photometric units based on visible light intensity. Color temperature relates to light color quality, not quantity, so it doesn’t impact the numerical conversion between lux and lumens.