Lumen to Lux Calculator

Easily convert between luminous flux (lumen) and illuminance (lux/fc)

Illuminance describes the amount of light reaching a surface and is measured in lux (lumens/m²) or foot-candles (lumens/ft²). Luminous Flux, on the other hand, describes the total light output of a light source and is measured in lumens. Since the same lumen output can spread across a larger or smaller area depending on the geometry, the calculator needs to know how the light is distributed — either by entering the illuminated area directly, or by entering the beam angle and distance to the source, which together define the cone of light.

⚠️ Note: Illuminance and luminous flux describe light as perceived by humans and should not be used for plant lighting.

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Common lumen to lux conversions

The table below shows illuminance (in lux) for common luminous-flux outputs (in lumens) across typical illuminated areas. For instance, 2,000 lumens over 1 m² equals 2,000 lux; the same 2,000 lumens spread over 5 m² equals 400 lux. Note: lumens and lux describe light by human vision — for plant lighting use PPFD.

Luminous Flux (lm)	0.5 m²	1 m²	2 m²	5 m²	10 m²
500	1,000	500	250	100	50
1,000	2,000	1,000	500	200	100
1,500	3,000	1,500	750	300	150
2,000	4,000	2,000	1,000	400	200
3,000	6,000	3,000	1,500	600	300
5,000	10,000	5,000	2,500	1,000	500
7,500	15,000	7,500	3,750	1,500	750
10,000	20,000	10,000	5,000	2,000	1,000
15,000	30,000	15,000	7,500	3,000	1,500
Formula: lux = lumens ÷ illuminated area (m²). Both lumens and lux describe light as perceived by humans — for plant lighting use PPFD instead.

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Lumen to Lux Calculator

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Common lumen to lux conversions

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