Candela to Lumen Calculator
Convert candela to lumens with step-by-step calculations. Perfect for LED specifications, lighting design, and photometric calculations.
Luminous Intensity to Luminous Flux Converter
Common Candela to Lumen Conversions
Click on these links to see instant conversions with common values:
Understanding Candela to Lumen Conversion
Converting candela to lumens involves transforming directional luminous intensity to total luminous flux. This conversion depends on the beam angle and how the light is distributed in space.
Conversion Formula
Where:
• lumens = luminous flux (total light output)
• candela = luminous intensity
• θ = beam angle in degrees
• π = 3.14159...
Key Concepts
- Candela (cd): Luminous intensity - the amount of light emitted in a particular direction
- Lumens (lm): Luminous flux - the total amount of visible light emitted by a source
- Beam Angle: The cone angle where the luminous intensity is at least 50% of the maximum
- Solid Angle: The three-dimensional angle subtended by the light beam (steradians)
Typical Light Source Intensities
| Light Source | Intensity (cd) | Beam Angle | Total Output (lm) |
|---|---|---|---|
| Candle | 1 | 360° | 12.6 lm |
| LED Flashlight | 5000 | 15° | 434 lm |
| Car Headlight | 25000 | 20° | 2147 lm |
| LED Spotlight | 1000 | 30° | 698 lm |
| Stage Light | 50000 | 10° | 1208 lm |
| LED Bulb | 80 | 120° | 502 lm |
Frequently Asked Questions
How do you convert candela to lumens?
Multiply candela by the solid angle: lumens = candela × (2π × (1 - cos(θ/2))). The beam angle determines the solid angle and affects total light output.
What is the relationship between candela and lumens?
Candela measures directional light intensity, while lumens measure total light output. A wider beam angle produces more lumens from the same candela rating.
What is a solid angle in lighting calculations?
A solid angle measures the three-dimensional cone of light emission in steradians. It determines how concentrated or spread out the light is, directly affecting the candela to lumen conversion.