Lux to lumens calculator

Illuminance in lux (lx) to luminous flux in lumens (lm) calculator and how to calculate.

Enter the illuminance in lux (lx), select area unit type, enter radius in meters for spherical light source or surface area

in square meters for any light source and press the Calculate button to get the luminous flux in lumens (lm):

Lux to lumens calculation formula

Lux to lumens calculation with area in square feet

The luminous flux Φ_V in lumens (lm) is equal to 0.09290304 times the illuminance E_v in lux (lx) times the surface area A in square feet (ft²):

Φ_V(lm) = 0.09290304 × E_v(lx) × A_(ft2₎

For a spherical light source, the area A is equal to 4 times pi times the squared sphere radius:

A = 4⋅π⋅r ²

So the luminous flux Φ_V in lumens (lm) is equal to 0.09290304 times the illuminance E_v in lux (lx) times 4 times pi times the squared sphere radius r in feet (ft):

Φ_V(lm) = 0.09290304 × E_v(lx) × 4⋅π⋅r_(ft) ²

So

lumens = 0.09290304 × lux × (square feet)

or

lm = 0.09290304 × lx × ft²

Lux to lumens calculation with area in square meters

The luminous flux Φ_V in lumens (lm) is equal to the illuminance E_v in lux (lx) times the surface area A in square meters (m²):

Φ_V(lm) = E_v(lx) × A_(m2₎

For a spherical light source, the area A is equal to 4 times pi times the squared sphere radius:

A = 4⋅π⋅r ²

So the luminous flux Φ_V in lumens (lm) is equal to the illuminance E_v in lux (lx) times 4 times pi times the squared sphere radius r in meters (m):

Φ_V(lm) = E_v(lx) × 4⋅π⋅r ²

So

lumens = lux × (square meters)

or

lm = lx × m²

Example

What is the luminous flux on a surface of 4 square meters and illuminance of 500 lux?

Φ_V(lm) = 500 lux × 4 m² = 2000 lm