Convert Lumens To Candlepower Calculator

Candlepower Formula:

\[ Candlepower = \frac{Lumens}{2\pi (1 - \cos(Beam Angle/2))} \]

Candlepower:

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1. What is Candlepower?

Candlepower is a measurement of luminous intensity that describes the concentration of light emitted in a specific direction. It is particularly useful for evaluating the performance of focused light sources like spotlights and flashlights.

2. How Does the Calculator Work?

The calculator uses the candlepower formula:

\[ Candlepower = \frac{Lumens}{2\pi (1 - \cos(Beam Angle/2))} \]

Where:

\( Lumens \) — Total luminous flux (lm)
\( Beam Angle \) — Angular width of the light beam (degrees)
\( \pi \) — Mathematical constant pi (≈3.14159)
\( \cos \) — Cosine trigonometric function

Explanation: The formula converts total light output (lumens) to directional intensity (candlepower) based on the beam's angular spread.

3. Importance of Candlepower Calculation

Details: Candlepower calculation is essential for lighting design, comparing spotlight performance, and ensuring proper illumination for specific applications where directional light intensity matters more than total light output.

4. Using the Calculator

Tips: Enter lumens (total light output) and beam angle (angular width of light beam in degrees). Both values must be positive numbers, with beam angle typically between 1-180 degrees.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between lumens and candlepower?
A: Lumens measure total light output in all directions, while candlepower measures light intensity in a specific direction.

Q2: When should I use candlepower instead of lumens?
A: Use candlepower when evaluating focused light sources like spotlights, flashlights, or any application where directional intensity is more important than total light output.

Q3: What is a typical beam angle range?
A: Beam angles typically range from 5° (very narrow spot) to 120° (wide flood), with most focused lights between 15°-60°.

Q4: Why does beam angle affect candlepower?
A: A narrower beam angle concentrates the same total light into a smaller area, resulting in higher candlepower (intensity) in that specific direction.

Q5: Can I convert candlepower back to lumens?
A: Yes, you can rearrange the formula: Lumens = Candlepower × 2π(1 - cos(Beam Angle/2)).