Watts to Lumens Calculator

What are Watts and Lumens?

Watts (W) is a unit of power that measures the rate of energy consumption. In lighting, it represents the amount of electricity a light bulb uses. Lumens (lm) is a unit of luminous flux, which measures the total amount of visible light emitted by a source. It quantifies how bright a light appears to the human eye.

The Watts to Lumens Formula

The formula for converting watts to lumens is:

\[\text{Lumens} = \text{Watts} \times \text{Luminous Efficacy}\]

Where:

• Lumens = Light output
• Watts = Power input
• Luminous Efficacy = Efficiency of the light source (lm/W)

Step-by-Step Watts to Lumens Calculation

1. Determine the power input in watts (W) of your light source.
2. Identify the luminous efficacy (lm/W) of your light source. This varies depending on the type of bulb.
3. Multiply the watts by the luminous efficacy to get the lumen output.

Example Calculation

Let's calculate the lumen output for a 60W incandescent light bulb:

1. Power input = 60W
2. Luminous efficacy of an incandescent bulb ≈ 15 lm/W
3. \[\begin{align} \text{Lumens} &= 60 \text{ W} \times 15 \text{ lm/W} \\ &= 900 \text{ lumens} \end{align}\]

Visual Representation

This diagram illustrates how a 60W incandescent light bulb produces approximately 900 lumens of light output. The yellow circle represents the relative brightness of the light source.