How to Calculate How Many Lumens per Square Foot I Need

When choosing the right lighting solutions for your space, the matter of lumens is bound to come up. While you may or may not have a passing understanding of lumens, it is helpful to have at least the basic principles under your belt to get the best results. Here are a few of the most common issues surrounding getting the right lumens for your space.

How Many Lumens Do I Need?

Many people confuse lumens needed because they think that more is automatically better. The truth is having the most concentrated or highest output of lumens may not be the best solution for the needs of the space. If you load up with too many lumens, you end up with an overpowering brightness that can lead to discomfort. If you opt for a lower lumen, you run the risk of it being too dim to accommodate the space. So, what do you do to remedy this problem? You follow a simple suggested calculation for figuring out lumens based on room size.

Lumens Calculator Room Size

The way to calculate how many lumens you need in a room is to consider a few aspects of the space. Using the width and the length of the room times to find your suggested lumens is easy. For example, if the room is 12 feet long in length and 10 feet wide in width, 12 feet times 10 feet equals 120 feet. Just remember that the way to calculate room size to find lumen is always length times width equals square foot.

How Many Lumens Per Square Foot?

Figuring out the size of the room with the above formula is only the first step in determining the lumens needed for the room. When lighting a room, you light it by suggested lumens per square foot. So, using the figure above as an example, you would be lighting for 120 feet based on 12x10 room. To figure out the lumens needed based on this figure, you would take the total lumens of the lamp you are considering using and divide it by the total square foot. This will tell you a figure of how many lumens are being used per square foot. From there, you can see if you are using the suggest number of lumens for the space.

Suggested Lumens Per Square Foot by Room

• Living rooms: 10–20 lumens

• Dining rooms: 30–40 lumens

• Bedrooms: 10–20 lumens

• Bathrooms: 70–80 lumens

• Hallways: 5–10 lumens

• Kitchens: 30–40 lumens

• Task Lighting: 70–80 lumens