30 lux corresponds to 30 lumens when the illuminated area is exactly 1 square meter. This means if a surface of 1 m² receives an illumination of 30 lux, it is receiving 30 lumens of luminous flux.
Lux measures illuminance, which is lumens spread over an area. Converting lux to lumens depends on the size of the surface being lit. When the area is 1 m², lux and lumens values are equal, but for other areas, lumens equals lux multiplied by area in square meters.
Conversion Tool
Result in lumens:
Conversion Formula
The formula to convert lux (lx) to lumens (lm) is lumens = lux × area (in square meters). Lux measures how much light hits a surface, while lumens measures total visible light emitted. To find lumens from lux, you need to know the area over which the lux measurement is taken. For example, if a surface of 2 square meters has an illuminance of 30 lux, the total luminous flux is:
lumens = 30 lux × 2 m² = 60 lumens
This works because lux tells you the brightness per unit area, so multiplying by area gives total light falling on that surface.
Conversion Example
- Convert 15 lux to lumens on a 3 m² surface:
- Multiply 15 lux × 3 m²
- Result: 45 lumens
- Convert 40 lux to lumens on 1.5 m²:
- 40 lux × 1.5 m² = 60 lumens
- Convert 50 lux over 2.2 m²:
- 50 × 2.2 = 110 lumens
- Convert 10 lux on 5 m²:
- 10 × 5 = 50 lumens
- Convert 25 lux on 0.8 m²:
- 25 × 0.8 = 20 lumens
Conversion Chart
Below is a chart showing lux values from 5.0 to 55.0 converted to lumens, assuming the illuminated area is 1 square meter. To read the chart, find the lux value in the first column and the corresponding lumens in the second column; the numbers are equal here because area is 1 m².
| Lux (lx) | Lumens (lm) |
|---|---|
| 5.0 | 5.0 |
| 10.0 | 10.0 |
| 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 |
Related Conversion Questions
- How many lumens does 30 lux produce on a 2 square meter surface?
- If a room measures 5 m² with 30 lux, what is the total lumens?
- What’s the difference between lux and lumens when converting 30 lux?
- Can 30 lux be directly converted to lumens without knowing area?
- How to calculate lumens from 30 lux for a 0.5 m² desk lamp?
- Does 30 lux equal 30 lumens for any surface size?
- Which formula applies when converting 30 lx to lumens in different areas?
Conversion Definitions
Lux: Lux is a measurement of illuminance describing how much luminous flux is spread over a given area, expressed as lumens per square meter. It quantifies the intensity of light hitting a surface, indicating perceived brightness from human eyes.
Lumens: Lumens measure the total quantity of visible light emitted from a source per unit time. It reflects the actual light output, independent of the area illuminated, and helps compare brightness between different light sources.
Conversion FAQs
Is it possible to convert lux to lumens without knowing the area?
No, converting lux to lumens requires knowing the surface area being illuminated, because lux measures light per unit area. Without area, you can’t calculate total lumens since lumens equals lux multiplied by the area.
Why do lux and lumens have the same numerical value sometimes?
They match numerically only when the illuminated area is exactly 1 square meter. Since lux equals lumens divided by area, if area is 1 m², lux and lumens values become identical.
Can lumens be higher than lux for the same light source?
Yes, lumens is total light output, and lux depends on how that light spreads over an area. A high lumen source on a large area may produce low lux, while a small area concentrates the same lumens into higher lux.
Does changing distance affect lux and lumens equally?
Distance affects lux because light spreads over larger area, reducing illuminance, but lumens remain constant as total light output doesn’t change with distance.
How accurate is converting 30 lux to lumens with assumed area?
The conversion’s accuracy depends on knowing the exact surface area. Assuming 1 m² is only accurate when that area matches the actual illuminated surface; otherwise, the lumens value will be off proportionally.
Last Updated : 04 July, 2025
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Sandeep Bhandari holds a Bachelor of Engineering in Computers from Thapar University (2006). He has 20 years of experience in the technology field. He has a keen interest in various technical fields, including database systems, computer networks, and programming. You can read more about him on his bio page.