Lighting 101: How to Select the Right Size Fixture

What size light fixture should I get for such-and-such room?

As an interior designer, this is a question I’m asked frequently. And for good reason. A fixture that’s on the smaller side will get lost in the space. Plus, it won’t provide enough light output. On the flip side, an oversized one will look out of proportion.

While it is always better to go too big than too small, there is a ‘trick’ to selecting the right overhead light fixture for any room.

1. To get the ideal diameter, measure the length and width of the room in feet. Add the two numbers together. Then, swap the value in feet for inches. For instance, say your dining room is 10 feet by 12 feet. 10 feet + 12 feet = a 22-inch wide light fixture. If you want something slightly larger to serve as a focal point, add 4 to 6 inches to the sum.

2. If looking for a pendant light fixture (as opposed to a flush or semi-flush mount), you’ll also want to determine the most desirable height. This requires you to measure the height of the room (floor to ceiling). Multiply the height by 2.5 to 3 inches per foot. Again, swap the value in feet for inches. For example, if your dining room has a 9-foot ceiling, 9 feet x 2.5 to 3 inches = a 22.5 to 27-inch tall light fixture.

So, for our dining room example, you’d look for a light fixture around 22 inches wide and 22.5 to 27 inches tall.

Once you’ve found a light fixture that’s a suitable size for your space, you’ll want to make sure it is hung at the correct height. Otherwise, your measurements, calculations and shopping trip will be for naught; a fixture hung too low or too high will look out of place. In a dining room with an 8-foot ceiling, allow 30 to 36 inches between the top of the table and the bottom of the light fixture. Add 3 inches of space for each additional foot of ceiling height.