What Is the Lumens to Candelas Converter?
Lumens (lm) measure total luminous flux emitted in all directions, whereas Candelas (cd) measure light intensity focused in a specific direction.
A narrow spotlight produces vastly higher candela intensity than a wide floodlight emitting the identical lumen count.
How Does the Lumens to Candelas Converter Work?
The calculator computes the conical solid angle Ω = 2π(1 - cos(θ/2)) in steradians.
Dividing total lumens by solid angle yields directional intensity in candelas (1 cd = 1 lm/sr).
Lumens to Candelas Converter Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Luminous intensity I in candelas equals total flux Φ in lumens divided by the solid angle Ω in steradians.
How to Use the Lumens to Candelas Converter
- Enter total fixture output in lumens.
- Enter the optical beam angle in degrees.
- Inspect peak candela intensity and solid angle in steradians.
Step-by-Step Example Calculation
1,000 Lumens at 30° Spotlight
Input Values:
Understanding Your Result
Flashlights with high candela ratings cast beams over extreme throw distances.
Room lighting fixtures favor low candela, wide-angle dispersion to illuminate evenly without glare.
Factors That Affect the Result
- Reflector and Lens Collimation: Sharper optical focus concentrates lumens into tighter beam angles.
- Beam Uniformity: Calculations assume a uniform conical beam profile.
When Should You Use This Calculator?
- Selecting automotive driving lamps, searchlights, and architectural spots.
- Evaluating flashlight throw distance (Throw = √(Candela × 4) meters).
Assumptions & Limitations
- Assumes uniform luminous intensity distribution across the cone apex.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Implements standard CIE solid angle geometric integration.