1 Lux to Lumen – Answer with Formula

1 lux equals 1 lumen per square meter. So, converting 1 lux to lumen depends on the area over which the light spreads.

Lux measures illuminance (light per unit area), while lumen measures luminous flux (total light output). To get lumen from lux, multiply lux by the area in square meters that is illuminated.

Conversion Tool

Conversion Formula

The formula to convert lux to lumen depends on the surface area the light is spreading over. Since lux equals lumen per square meter, lumen can be found by multiplying lux by the area in square meters:

Lumen (lm) = Lux (lx) × Area (m²)

This works because lux measures how much light hits a surface, so knowing the size of that surface, you multiply lux by area to get total light output in lumens.

Example:

• If you have 1 lux shining on 2 m², then lumen = 1 lx × 2 m² = 2 lm.
• With 5 lux on 3 m²: lumen = 5 lx × 3 m² = 15 lm.

Conversion Example

• Convert 4 lux over 2 m²:
  • Multiply 4 lx by 2 m².
  • Result: 8 lumens.
• Convert 10 lux over 0.5 m²:
  • 10 lx × 0.5 m² = 5 lumens.
• Convert 7.5 lux on 3 m²:
  • 7.5 lx multiplied by 3 m² equals 22.5 lumens.
• Convert 0.2 lux over 10 m²:
  • 0.2 lx × 10 m² = 2 lumens.
• Convert 15 lux on 4 m²:
  • 15 lx times 4 m² equals 60 lumens.

Conversion Chart

The chart shows lux values from -24.0 to 26.0 assuming the illuminated area is 1 square meter, so the lumen value equals lux times 1. You can use it by picking the lux value and reading the corresponding lumen output for that area.

Related Conversion Questions

• How do I convert 1 lux into lumens if the area is unknown?
• What is the lumen output for 1 lux on a 5 square meter surface?
• Does 1 lux always equal 1 lumen?
• How to calculate lumen from lux for a room lighting setup?
• Is it possible to convert 1 lux directly to lumens without area?
• What does 1 lux mean in terms of total light emitted in lumens?
• How does changing the surface area affect lumen value when converting from 1 lux?

Conversion Definitions

Lux: Lux is a unit measuring illuminance, or how much luminous flux falls on a surface per unit area. One lux equals one lumen per square meter. It quantifies perceived brightness at a particular spot, helping evaluate lighting conditions for visibility and comfort.

Lumen: Lumen measures luminous flux, the total quantity of visible light emitted by a source in all directions per second. It represents brightness perceived by human eyes, regardless of the area the light covers or direction.

Conversion FAQs

Can lux have negative values when converting to lumen?

Lux itself should not be negative since it represents illumination intensity, which can’t be less than zero. Negative values in charts or calculations might appear due to measurement errors or hypothetical examples, but physically, lux and lumen values are non-negative.

Why does converting 1 lux to lumen require knowing the area?

Because lux represents light per unit area, without knowing the size of the surface illuminated, you cannot determine the total light output in lumens. Lumens measure total light emitted, so area is necessary to scale lux values properly.

What happens if the area changes after measuring 1 lux?

If the area increases, lumens increase proportionally since lumens equal lux multiplied by area. For the same lux value, doubling the area doubles the lumens. This shows how distribution affects total light output.

Is it possible to convert lumens directly to lux without area?

No, because lux depends on both the amount of light (lumens) and the area over which it spreads. Without area, you can’t calculate lux from lumens or vice versa accurately.

Does the shape of the illuminated surface affect lux to lumen conversion?

The shape does not directly affect the mathematical conversion, only the total area matters. However, shape influences light distribution and intensity variations which can impact practical measurements but not the basic formula.