Lumens to candela calculator

Lumens to candela calculator

We are offering the Lumens (lm) to candela (cd) calculator to help you make calculations easy.

Lumens to candela calculator

Enter the value of luminous flux in lumens, add the value of apex angles in degrees and hit the = button to obtain the luminous intensity measured in candela.

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

Lumens to candela calculation

For the uniform or isotropic light source, the luminous intensity Iv in candela (cd) is apparently equal to the value of luminous flux Φv in lumens (lm), which is later divided by the solid angle Ω measured in steradians (sr).

Iv(cd) = Φv(lm) / Ω(sr)

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

Ω(sr) = 2π(1 – cos(θ/2))

The luminous intensity Iv measured in candela (cd) is apparently equal to the luminous flux Φv which is measured in lumens (lm), and divided by twice the value of pi times 1 minus cosine of half apex angle θ measured in degrees (º):

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

So the value becomes,

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

Or you can say,

cd = lm / ( 2π(1 – cos(º/2)) )

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