Enter the area and required lumen per square foot into the calculator to determine the number of Par (Lumen Light) required.

Par (Lumen Light) Formula

The following formula is used to calculate the number of Par (Lumen Light) required for a specific area.

PL = (A * L) / E

Variables:

  • PL is the number of Par (Lumen Light) required
  • A is the area in square feet
  • L is the required lumen per square foot
  • E is the efficiency of the light source (lumen per watt)

To calculate the number of Par (Lumen Light) required, multiply the area in square feet by the required lumen per square foot. Then divide the result by the efficiency of the light source in lumen per watt.

What is a Par (Lumen Light)?

A Par (Parabolic Aluminized Reflector) Lumen Light is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It utilizes a parabolic reflector to direct the light, and an aluminized coating to enhance its brightness. The term “lumen” refers to the measure of the total quantity of visible light emitted by a source, indicating the light output or brightness of the lamp. Therefore, a Par Lumen Light is a high-intensity light source that provides a significant amount of visible light.

How to Calculate Par (Lumen Light)?

The following steps outline how to calculate the number of Par (Lumen Light) required.


  1. First, determine the area in square feet (A).
  2. Next, determine the required lumen per square foot (L).
  3. Next, determine the efficiency of the light source (E) in lumen per watt.
  4. Next, gather the formula from above = PL = (A * L) / E.
  5. Finally, calculate the number of Par (Lumen Light) required.
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

area in square feet (A) = 100

required lumen per square foot (L) = 20

efficiency of the light source (E) = 0.8