How much light is enough to light a room?

The lumen method is the most commonly used for calculating the total light output needed for your space. With this formula, you first establish the intended use of the space, then you measure its square footage.

Total Lumens Needed=Footcandle Requirement X Room Size(square footage)

First: Establish the footcandle requirement for your application.
Lighting requirements vary depending on the type of room being lit, also known as the application. For example, a bathroom or kitchen will require more foot candles than a living room or bedroom. Once you establish the intended use of your space, browse this footcandle chart for the IES-recommended footcandle requirement for your application.

Second: Determine room size by square footage.
Multiply the length times the width of the room to get the room square footage. For example, if the room is 10 feet wide and 10 feet long, the room square footage will be 100 square feet.

Let’s recap how to gauge how much light you need for a space. Multiply your room square footage by the footcandle requirement. For example, a 100-square foot living room, which needs 20 foot candles, will need 2,000 lumens. A 100-square foot dining room, which needs 40 foot-candles, will need 4,000 lumens.