1. What is a Lumen to Candlepower Calculator?

Definition: This calculator converts luminous flux (lumens) to candlepower (assuming an isotropic light source).

Purpose: It helps lighting professionals and enthusiasts understand the relationship between these two important photometric units.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Candlepower — Luminous intensity (candela or cp)
• Lumens — Total luminous flux (lm)
• 4π — Solid angle of a sphere (steradians)

Explanation: This conversion assumes the light source emits equally in all directions (isotropic). 1 candlepower is approximately equal to 1 candela.

3. Importance of Lumen to Candlepower Conversion

Details: Understanding this relationship helps in lighting design, comparing light sources, and meeting specific illumination requirements.

4. Using the Calculator

Tips: Simply enter the luminous flux in lumens. The value must be > 0.

5. Frequently Asked Questions (FAQ)

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

Q2: When is this conversion accurate?
A: Only for isotropic (uniform in all directions) light sources. Real-world sources often have directional intensity patterns.

Q3: What is 4π in the formula?
A: It represents the total solid angle (steradians) of a sphere, since lumens are spread over all directions.

Q4: How does candlepower relate to candela?
A: 1 candlepower ≈ 1 candela. Candlepower is the older term, while candela is the SI unit.

Q5: Why would I need this conversion?
A: Useful when you know total light output but need to understand directional intensity, or when working with specifications that use different units.