Candela to Lumens Converter

Convert luminous intensity (candela) to luminous flux (lumens) based on the beam angle of the light source.

cd
degrees

Lumens

314.2

Candela to Lumens

Lumens = Candela x 2pi x (1 - cos(theta/2))

Where theta is the beam angle in radians.

  • Candela measures intensity in a specific direction
  • Lumens measure total light output in all directions of the beam
  • A narrow-beam spotlight and a wide floodlight can have the same candela but very different lumens.

    Example Calculation

    100 candela light source with 120° beam angle.

    1. 01theta/2 = 60° = pi/3 radians
    2. 02cos(60°) = 0.5
    3. 03Lumens = 100 x 2pi x (1 - 0.5) = 314.2 lumens

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