Candela to Lumens Calculator
Enter candela and the beam solid angle in steradians. The calculator applies lumens = candela × steradians.
Estimated lumens:
A QUICK WALKTHROUGH
How to use this tool
- Enter the luminous intensity in candela (cd).
- Enter the beam solid angle in steradians (sr).
- Calculate the estimated luminous flux in lumens (lm).
A beam angle is required
Candela measures luminous intensity in a direction, while lumens measure total luminous flux. There is no single candela-to-lumens conversion without the beam solid angle or an equivalent distribution assumption.
User-supplied distribution
This calculator assumes the entered candela value applies uniformly across the entered solid angle. It does not infer a beam pattern, fixture optics, or total lamp output.
Formula
For this stated assumption, luminous flux in lumens = luminous intensity in candela × solid angle in steradians.
GOOD TO KNOW
Common questions
Can candela be converted to lumens directly?
No. Enter a beam solid angle or another valid light-distribution assumption; the tool then uses lm = cd × sr.
What does steradian mean here?
It is the unit of solid angle. A full sphere is 4π sr, while a narrower beam occupies fewer steradians.