# Lumens to candela calculator

Lumens (lm) to candela (cd) calculator and how to calculate.

## Lumens to candela calculator

Enter the luminous flux in lumens, apex angle in degrees and press the Calculate button to get the luminous intensity in candela:

 Enter luminous flux in lumens: lm Enter apex angle in degrees: º Luminous intensity result in candela: cd

#### Lumens to candela

The Lux or Candela lumens calculator below will help you choose the lighting solution that best meets the specific requirements of your installation. Airfal offers a wide range of high quality and energy efficient LED lights for a wide range of industrial applications and to meet multiple technical requirements.

With this calculator, you can convert a lumens value of a product into a lux value if you know the beam angle and measurement distance. Enter the distance and angle of the beam, then enter a lumens value and click on’Convert to Lux’ or a Lux value and click on’Convert to Lumens’. You can also convert to Candelas.

Iluminance (lux): the iluminance refers to the incidence of the light flux on a surface, per unit of surface
The unit of illumination is the lumen per square metre: lux (lux). A single lux is equal to one lumen per square meter.

Luminous flux (Lm): Total amount of light emitted in all directions by the light source. The lumen (unit lm) gives the total luminous flux of a light source by multiplying the intensity (in candela) by the angular span over which the light is emitted. .

Here are some examples:

Candle 12 lm
Incandescent lamp 60 W 750 lm
LED 1 W 130 lm 130 lm

For example, a 1 candela light source will produce 1 lumen per square meter at a distance of 1 meter.
A lux is equal to one lumen per square meter (lux = lumens/m2).

#### Lumens to candela calculation

For uniform, isotropic light source, the luminous intensity Iv in candela (cd) is equal to the luminous flux Φv in lumens (lm),

divided by the solid angle Ω in steradians (sr):

Iv(cd) = Φv(lm) / Ω(sr)

The solid angle Ω in steradians (sr) is equal to 2 times pi times 1 minus cosine of half the cone apex angle θ in degrees (º):

Ω(sr) = 2π(1 - cos(θ/2))

The luminous intensity Iv in candela (cd) is equal to the luminous flux Φv in lumens (lm),

divided by 2 times pi times 1 minus cosine of half the apex angle θ in degrees (º):

Iv(cd) = Φv(lm) / ( 2π(1 - cos(θ/2)) )

So

candela = lumens / ( 2π(1 - cos(degrees/2)) )

Or

cd = lm / ( 2π(1 - cos(º/2)) )