Enter the area of the room and the lighting requirement into the calculator to determine the lumen requirement. This calculator can also evaluate any of the variables given the others are known.

Lumen Requirement Formula

The following formula is used to calculate the lumen requirement for a room.

LR = A * L


  • LR is the lumen requirement (lumens) A is the area of the room (square feet) L is the lighting requirement (lumens per square foot)

To calculate the lumen requirement, multiply the area of the room by the lighting requirement. The result will be the total lumen requirement for the room.

What is a Lumen Requirement?

A lumen requirement refers to the amount of light needed in a particular space or for a specific task. Lumens are a measure of the total amount of visible light emitted by a source. The lumen requirement for a space is determined by factors such as the size of the space, the color of the walls and ceiling, the type of tasks being performed, and the personal preference of the occupants. This requirement is crucial in designing lighting systems for both residential and commercial spaces to ensure adequate visibility and comfort.

How to Calculate Lumen Requirement?

The following steps outline how to calculate the Lumen Requirement.

  1. First, determine the area of the room (A) in square feet.
  2. Next, determine the lighting requirement (L) in lumens per square foot.
  3. Next, gather the formula from above = LR = A * L.
  4. Finally, calculate the Lumen Requirement.
  5. 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 of the room (A) = 250 square feet

Lighting requirement (L) = 20 lumens per square foot