How Many Recessed Lights?

How Many Recessed Lights?

When deciding how many recessed lights a room needs, it’s important that you get it right.
Having too many lights can be distracting and look unnatural. At the same time, it would be a huge disappointment if you were to complete an installation only to discover that it wasn’t enough lights to adequately light the room.

Determining how many recessed lights a room needs and how bright they should be are the first steps in planning for general lighting.

Once you know how many lights a room needs, you can plan the layout and calculate their placement.
And once you know how bright they should be, you can choose the size and type of recessed lights you’d like to use.


It will give you my recommended number of recessed lights for general lighting in a room, and also their recommended brightness. It assumes you will be using BR flood type lamps or LEDs with a 50-degree beam angle or wider.

The formulas are based off the results from thousands of installations, and will ensure you have adequate coverage and brightness for any room.

Because there are several variables among rooms such as ceiling height, room shape, wall and floor reflectance, etc., use the calculator as a starting point. You may need to add or subtract a light or two depending on the room.


How to Measure a Room for Recessed Lighting

For general lighting,  we want to light the room- not the furniture or other objects in the room. So pretend that the room is empty if it’s not and use a tape measure to measure the length and the width of the room between the walls.

If you have a large room or an open floor plan, think of each living area within as a separate “room” when calculating the number of lights. In the example below, you can see a typical open floor plan that combines a kitchen, dining nook, and family room.
Image of a reflected ceiling plan


Now take a look at the next example. You can see how each “room” is defined for measuring and calculating the number of lights separately.
Image of a room with segments for calculating how many recessed lights each area will need


Does ceiling height matter?

A common misconception is that tall ceilings require more lights, when actually the opposite is true.
Light shines downward from a recessed fixture in the shape of a cone, and for general lighting the cones of light should intersect at least 30 inches above the floor. Tall ceilings allow the cones of light more distance to spread so they’ll easily intersect above that level.

So rather than using more lights, use brighter lights.

If the lights will be installed in a ceiling taller than 16 feet, you may want to use PAR type light bulbs. They have a tighter beam control which will get more of the light down from the ceiling to the living area.