Candela Calculator
Convert luminous flux & beam angle to peak candela using a solid-angle model.
lm
Use total output in lumens. Example: 500 lm.
°
0.5°
120°
Half-angle θ = (beam° ÷ 2).
Candela (cd) ≈ 0.00
Enter values and press Calculate (or change inputs for live update).
Model
Solid angle
Peak candela (approx.)
Solid angle
ω = 2π(1 − cos θ), where θ is the half-angle in radians (θ = (beam° ÷ 2) × π/180).Peak candela (approx.)
cd = lumens ÷ ω.
Notes
• Real beams aren’t perfectly uniform; hotspot/spill affects effective candela.
• Narrower beams → higher candela; wider beams → lower candela.
• Real beams aren’t perfectly uniform; hotspot/spill affects effective candela.
• Narrower beams → higher candela; wider beams → lower candela.
