There are two ways to determine this number and it depends on the number of blades on the fan.
Ceiling fan size in inches.
When you go ceiling fan shopping you will notice that the size of the fan is measured in inches.
In the last several years there has been a huge influx of larger diameter residential ceiling fans hit the market and the most popular size is now the 60 ceiling fan.
This is called the sweep or the blade span of the fan.
This includes large bathrooms large bedrooms medium sized living rooms and kitchens.
Most ceiling fans are between 42 and 48 inches in size and that they work well for spaces from 75 to 175 square feet.
36 48 and so on.
Ceiling fans come in a wide range of blade spans from small mini fans with a blade span of 18 inches up to large ceiling fans with a 68 inch blade span.
Ceiling fans between 42 and 48 inches.
For larger rooms with a square footage around 225 a 50 to 54 inch 130 to 140 cm blade.
For rooms between 75 and 144 square feet your ceiling fan should have a diameter of 36 to 42 inches.
A decade ago ceiling fans were pretty much only available in 42 48 and 52.
In terms of sizing your ceiling fan for your bedroom there are two common size options for bedrooms.
For rooms 75 square feet or smaller your ceiling fan should be 36 inches 91 4 cm or less in diameter.
If you have a regular sized bedroom of 144 to 225 square feet then a medium ceiling fan with a blade span of 44 to 50 inches will be a great fit.