Lumens to Candela Calculator
Calculate luminous intensity from total luminous flux and beam spread.
I_v(cd) = Φ_v(lm) / [2π(1 - cos(½θ))]
1000 lm with 120° angle = 1000 / [2π(1 - cos(60°))] ≈ 318.3 cd
How do I convert lumens to candela?
To convert lumens (luminous flux) to candela (luminous intensity), you need to know the apex angle of the light beam. The formula is: Candela = Lumens / (2π * (1 - cos(0.5 * angle))).
What is the difference between lumens and candela?
Lumens measure the total amount of light emitted by a source in all directions. Candela measures the amount of light emitted in a specific direction (the intensity within a solid angle).
What is a steradian?
A steradian (sr) is the SI unit of solid angle. A full sphere has a solid angle of 4π steradians. Lumens per steradian equals candela.
🔗 Related Calculators
📐 Formula
I_v(cd) = Φ_v(lm) / [2π(1 - cos(½θ))]
📝 Example Calculation
1000 lm with 120° angle = 1000 / [2π(1 - cos(60°))] ≈ 318.3 cd
❓ Frequently Asked Questions
How do I convert lumens to candela?▼
To convert lumens (luminous flux) to candela (luminous intensity), you need to know the apex angle of the light beam. The formula is: Candela = Lumens / (2π * (1 - cos(0.5 * angle))).
What is the difference between lumens and candela?▼
Lumens measure the total amount of light emitted by a source in all directions. Candela measures the amount of light emitted in a specific direction (the intensity within a solid angle).
What is a steradian?▼
A steradian (sr) is the SI unit of solid angle. A full sphere has a solid angle of 4π steradians. Lumens per steradian equals candela.