# Lumens to Watts Calculator

Calculating the conversion between luminous flux and electric power is essential for optimizing and understanding lighting efficiency.

Luminous flux, measured in lumens, indicates the total amount of visible light emitted by a source. By determining how effectively a light source converts electrical energy into visible light, one can measure its luminous efficacy, represented in lumens per watt.

Using a simple method, individuals can input the desired luminous flux and luminous efficacy values to determine the power, in watts, required to produce that level of brightness.

This approach helps to evaluate the performance of various light sources by analyzing their efficacy values, which are typically average numbers, and assists in making informed decisions about energy use.

## Conversion from Lumens to Power in Watts

The power in watts for a light source is found by dividing its brightness, in lumens, by its efficiency, measured in lumens per watt.

This method helps compare how much power different light bulbs use. Energy-saving bulbs like LEDs and fluorescents provide more brightness with less energy used.

### Lumens to Watts Reference Chart

Lumens | Incandescent (W) | LED/Fluorescent (W) |
---|---|---|

375 lm | 25 W | 6.23 W |

600 lm | 40 W | 10 W |

900 lm | 60 W | 15 W |

1125 lm | 75 W | 18.75 W |

1500 lm | 100 W | 25 W |

2250 lm | 150 W | 37.5 W |

3000 lm | 200 W | 50 W |

This chart shows different luminance and their power usage for traditional and energy-saving light sources.

## Converting Brightness in Lumens to Power in Watts

### Chart of Light Efficiency

Luminous efficacy measures how effectively a light source converts electricity into light. It is often expressed in lumens per watt (lm/W). Here’s a simple table to illustrate various light types and their usual efficacies:

Light Type | Efficacy (lm/W) |
---|---|

Incandescent | 10-17 |

Halogen | 16-24 |

CFL | 35-100 |

LED | 80-100+ |

### Brightness to Power Table

To find out how much power in watts a light uses based on its lumens, use the equation: **Watts = Lumens / (Lumens per watt)**. Below is an example table:

Lumens | Efficacy (lm/W) | Watts |
---|---|---|

800 | 10 | 80 |

800 | 20 | 40 |

800 | 100 | 8 |