Lumens to Watts Calculator: Convert Light Output to Electrical Power

Calculate Watts from Lumens and Luminous Efficacy

lm
The total amount of visible light emitted by the source.
lm/W
How efficiently the light source converts electricity into light. Use typical values provided above.

Quickly determine the electrical power consumption of your lighting fixtures with our Lumens to Watts Calculator. Input lumens and light source efficacy to find the exact wattage required, helping you choose energy-efficient lighting solutions like LEDs or understand existing setups. Perfect for lighting designers and DIY enthusiasts.

Formula:

The fundamental formula to convert luminous flux (lumens) to electrical power (watts) is:

Watts = Lumens / Luminous Efficacy (lm/W)

Where:

  • Watts (W): Represents the electrical power consumed by the light source.
  • Lumens (lm): Denotes the total amount of visible light emitted by a light source.
  • Luminous Efficacy (lm/W): Is a measure of how efficiently a light source converts electrical power into visible light. This value varies significantly by bulb type:
    • Incandescent bulbs: ~10-17 lm/W
    • Halogen bulbs: ~15-25 lm/W
    • Fluorescent tubes: ~50-100 lm/W
    • LEDs: ~80-150+ lm/W

Electrical and Tools

1/4 Mile ET : Estimate Your Quarter Mile Elapsed Time

Go to Calculator

1x1 Matrix Multiplication

Go to Calculator

3D Distance : Find Distance Between Two Points in 3D Space

Go to Calculator

5x5 Matrix Multiplication

Go to Calculator

65th Percentile : Find the 65th Percentile Online

Go to Calculator

75th Percentile : Quickly Find Q3 for Your Dataset

Go to Calculator