Lux to Lumen 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 Lux to Lumen Conversions

The table below shows total luminous flux (in lumens) for common illuminance levels (in lux) across typical illuminated areas. For instance, 1,000 lux over 1 m² equals 1,000 lumens; 1,000 lux over 10 m² equals 10,000 lumens. Note: lumens and lux describe light by human vision — for plant lighting use PPFD.

Illuminance (lx)	1 m²	2 m²	5 m²	10 m²	20 m²
100	100	200	500	1,000	2,000
250	250	500	1,250	2,500	5,000
500	500	1,000	2,500	5,000	10,000
1,000	1,000	2,000	5,000	10,000	20,000
2,000	2,000	4,000	10,000	20,000	40,000
5,000	5,000	10,000	25,000	50,000	100,000
10,000	10,000	20,000	50,000	100,000	200,000

Formula: lumens = lux × illuminated area (m²). Both lumens and lux describe light as perceived by humans — for plant lighting use PPFD instead.

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Lux to Lumen Calculator

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Common Lux to Lumen Conversions

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