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Calculate luminous flux (lm) from luminous intensity (cd) and apex angle (°)

This calculator allows calculation of luminous flux (lm) from luminous intensity (cd) and apex angle (°).

LEDs are often described as having some luminous intensity and a viewing angle. This calculator will give the total luminous flux.

The calculator assumes uniform flux distribution though the apex angle, but in reality flux will vary. Using a lower 'average' luminous intensity is one method of adjusting for non-uniform distribution.

If power is provided, it also calculates luminous efficiency.

If radius is given, it also calculates luminous flux.

The results can serve as a saneness test on published product claims.

Inputs:
     
Luminous intensity (cd)  
Apex angle (°):  
Power (W):  
Radius (m)  
Results:
Luminous flux (lm)  
Luminous efficiency (lm/W)  
Luminous flux density (lx)  

The calculator does not do a lot of error checking, if you enter nonsense, it will probably produce nonsense.

Links

Changes

Version Date Description
1.01 14/04/2016 Initial.
1.02    
1.03    
1.04    
1.05    

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