# Online Lumens to candela Calculator

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# 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:

#### 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 i*luminance* 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 *I*_{v} in candela (cd) is equal
to the luminous flux Φ_{v }in lumens (lm),

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

*I*_{v(cd)} = *Φ*_{v(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 *I*_{v} in candela (cd) is equal to the luminous flux Φ_{v }in lumens (lm),

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

*I*_{v(cd)} = *Φ*_{v(lm)} / ( 2π(1 - cos(*θ*/2)) )

So

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

Or

cd = lm / ( 2π(1 - cos(º/2)) )