## Lumen Calculator ▼

## Lux Calculator ▼

## PPFD Calculator ▼

## How to calculate Lumens

Calculating lumens is essential for determining the amount of light needed for a specific area. Lumens measure the total quantity of visible light emitted by a source.

### Steps to Calculate Lumens

**Measure the Area:**Determine the dimensions of the area you want to illuminate. Calculate the area in square meters (or square feet).**Determine the Lux Requirement:**Lux is the measurement of light intensity. Different areas require different lux levels. For example, a living room might need 100-200 lux, while an office might need 300-500 lux.**Calculate Lumens:**Use the formula:\[ \text{Lumens} = \text{Lux} \times \text{Area} \]

For example, if you have a 20 square meter room that requires 150 lux, the calculation would be:

\[ \text{Lumens} = 150 \, \text{lux} \times 20 \, \text{m}^2 = 3000 \, \text{lumens} \]

## How to Calculate Lumens from Lux

Calculating lumens from lux is essential for determining the total light output needed for a specific area. Lumens measure the total quantity of visible light emitted by a source, while lux measures the illuminance or light intensity on a surface.

### Steps to Calculate Lumens from Lux

**Measure the Area:**Determine the area over which the light is spread. This is usually measured in square meters (m²).**Determine the Lux:**Lux is a measure of illuminance, or how much light is hitting a surface. This value is usually provided by the lighting manufacturer or can be measured using a lux meter.**Calculate Lumens:**Use the formula:\[ \text{Lumens} = \text{Lux} \times \text{Area} \]

For example, if you have a room that is 10 square meters and the illuminance is 150 lux, the calculation would be:

\[ \text{Lumens} = 150 \, \text{lux} \times 10 \, \text{m}^2 = 1500 \, \text{lumens} \]

### How to calculate Candela from Lumens

Let's assume the following values:

- Lumens = 1000 lm
- Apex Angle = 30 degrees

Using the formula:

\[ cd = \frac{1000}{2 \pi (1 - \cos(30 / 2))} \]

Evaluating:

\[ cd = \frac{1000}{2 \pi (1 - \cos(15))} \]

The Candela is approximately 136.6225 cd.

### How to Calculate Lumen To Watt?

The formula to calculate Watts (\(W\)) from Lumens (\(lm\)) is:

\[ W = \frac{lm}{lm/W} \]

Where:

- \(W\) is the power in watts.
- \(lm\) is the luminous flux in lumens.
- \(lm/W\) is the luminous efficacy in lumens per watt.

### How to Calculate LUX To Footcandles?

The formula to calculate Footcandles (\(fc\)) from Lux (\(lx\)) is:

\[ fc = \frac{lx}{10.76391} \]

Where:

- \(fc\) is the illuminance in footcandles.
- \(lx\) is the illuminance in lux.
- 10.76391 is the conversion factor from square meters to square feet.

### How to Calculate Lux to Watt?

The formula to calculate Watts (\(W\)) from Lux (\(lx\)) is:

\[ W = \frac{lx}{lm/W} \]

Where:

- \(W\) is the power in watts.
- \(lx\) is the illuminance in lux.
- \(lm/W\) is the luminous efficacy in lumens per watt.

### Units of Light

Unit | Symbol | Description |
---|---|---|

Lumen | lm | Measures the total amount of visible light emitted by a source. |

Foot-Candle | fc | Measures the amount of light received on a surface per square foot. |

Lux | lx | Measures the amount of light received on a surface per square meter. |

Candela | cd | Measures the luminous intensity in a specific direction. |

Luminous Efficacy | lm/W | Measures the efficiency of a light source in converting electrical power to visible light. |

### Lumens vs Lux Frequently Asked Questions

**What is Lumens (lm)?**

Answer: Lumens (lm) are a measure of the total amount of visible light emitted by a light source in all directions. It indicates the brightness or luminous flux of the light, regardless of how it is distributed.

**What is Lux (lx)?**

Answer: Lux (lx) is a measure of the amount of light received by a surface, specifically the illumination or luminous intensity per unit area. It is a measure of the brightness of a particular area or space, taking into account the distribution of light.

**How are Lumens and Lux Related?**

Answer: Lumens and Lux are related in that both measure aspects of light, but they do so in different ways. Lumens measure the total light output of a source, while Lux measures the brightness of a specific area illuminated by that source. The relationship between them depends on the size of the illuminated area and the distribution of light.

**Why are Lumens and Lux Important?**

Answer: Understanding Lumens and Lux is crucial in lighting design because it allows designers to determine the appropriate level of illumination for a space based on its intended use. Lumens help in selecting the right light source, while Lux ensures that the space is adequately lit for visibility, comfort, and energy efficiency.