Candela to lumens calculator

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

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

Lumens to candela calculator ►

Candela to lumens calculation

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 apex angle θ in degrees (º):

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 (º):

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

So

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

Or

lm = cd × ( 2π(1 - cos(º/2)) )

 

Candela to lumens calculation ►

 


See also

Write how to improve this page

  URL
  Name
  E-mail