Lumens to candela calculator

Lumens to candela calculator

How to calculate Lumens (lm) to candela (cd)

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


Footcandles to lux calculator

calculation of Lumens to candela

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

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