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Candela to lumens convert or conversion calculator

Candela (cd) to lumens (lm) calculator and how to calculate or how to use it .

Candela to lumens converter

Enter the luminous flux in lumens, apex angle in degrees and press the Calculate button

to get the luminous intensity in candela:



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



Candela to lumens calculation with formulas

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

times the solid angle Ω in steradians (sr):

Φv(lm) = Iv(cd) × 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 (°):

Ω(sr) = 2π(1 - cos(θ/2))

 

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

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

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

So

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

Or

lm = cd × ( 2π(1 - cos(°/2)) )