1 lux equals 1 lumen per square meter. So, converting 1 lux to lumens depends on the area you are measuring, but for an area of 1 square meter, 1 lux equals 1 lumen.
Lux measures illuminance, or how much light hits a surface, while lumens measure total light output. To convert lux to lumens, you multiply lux by the surface area in square meters that is illuminated; without knowing the area, you cannot get absolute lumens from lux alone.
Conversion Tool
Result in lumens:
Conversion Formula
The formula to convert lux to lumens is:
Lumens = Lux × Area (in square meters)
Lux measures the amount of light on a surface per unit area, so to find total light output in lumens, you multiply lux by the surface area the light covers. For example, if a surface receives 1 lux and the area is 1 square meter, the total lumens is 1 × 1 = 1 lumen.
If the area is larger, say 5 square meters, then lumens = 1 lux × 5 m² = 5 lumens.
Conversion Example
- Convert 3 lux over 2 square meters:
- Multiply lux by area: 3 × 2 = 6 lumens.
- This means the total light output falling on 2 square meters is 6 lumens.
- Convert 10 lux on 0.5 square meters:
- 10 × 0.5 = 5 lumens.
- The surface receives 5 lumens total of light.
- Convert 0.75 lux on 4 square meters:
- 0.75 × 4 = 3 lumens.
- So, 3 lumens light is spread over 4 square meters.
- Convert 15 lux on 1.2 square meters:
- 15 × 1.2 = 18 lumens.
- Total luminous flux hitting the surface is 18 lumens.
- Convert 0.1 lux over 10 square meters:
- 0.1 × 10 = 1 lumen.
- The light intensity is low but over a larger surface area.
Conversion Chart
| Lux | Lumens (Area = 1 m²) |
|---|---|
| -24.0 | -24.0 |
| -20.0 | -20.0 |
| -16.0 | -16.0 |
| -12.0 | -12.0 |
| -8.0 | -8.0 |
| -4.0 | -4.0 |
| 0.0 | 0.0 |
| 4.0 | 4.0 |
| 8.0 | 8.0 |
| 12.0 | 12.0 |
| 16.0 | 16.0 |
| 20.0 | 20.0 |
| 24.0 | 24.0 |
| 26.0 | 26.0 |
This chart shows the lumens equivalent for lux values assuming the surface area is 1 square meter. To get lumens for other area sizes, multiply the lumens value here by the actual area.
Related Conversion Questions
- How many lumens does 1 lux produce on a 2 square meter surface?
- Can I convert 1 lux to lumens without knowing the surface area?
- What is the difference between 1 lux and 1 lumen in lighting terms?
- If I have 1 lux of illuminance, how many lumens is that for 5 square meters?
- Does 1 lux correspond to a fixed number of lumens?
- How to calculate lumens from 1 lux lighting in a room?
- Why does converting 1 lux to lumens require area measurement?
Conversion Definitions
Lux: Lux is the unit that measures illuminance, the amount of light that falls on a surface per unit area. One lux equals one lumen per square meter. It tells how brightly a surface is lit but doesn’t measure the total emitted light.
Lumens: Lumens measure luminous flux, the total quantity of visible light emitted by a source per second. It indicates how much light is produced, regardless of the direction or area illuminated, unlike lux which is area-dependent.
Conversion FAQs
Can I convert lux directly to lumens without knowing the surface area?
No, lux alone isn’t enough to find lumens because lux measures light per unit area. Without the surface area, you don’t know the total light output. You must multiply lux by the area in square meters to get lumens.
Why would lux values be negative in some charts or calculations?
Negative lux values don’t have physical meaning since illuminance can’t be negative. Negative numbers may appear in mathematical models or errors but should be treated as invalid in lighting contexts.
Does a higher lux value always mean more lumens?
Not necessarily; lux depends on both lumens and area. A higher lux means more light per unit area, but if the area is small, total lumens can be low. Lumens represent total output, while lux shows intensity on a surface.
Is the conversion the same for all types of light sources?
The conversion formula doesn’t depend on the light source type; it only relates lux, lumens, and area. However, different sources emit light differently, affecting distribution but not the mathematical conversion.
How accurate is it to assume 1 square meter area for lux to lumens conversion?
Assuming 1 m² is a simplification for quick calculations. Real surfaces vary in size, so exact lumens need the actual area to be accurate. Using 1 m² is only accurate if the illuminated surface is exactly that size.