A replacement fan blade is the size of the circle of the entire fan blade when measuring the diameter of the fan from one side to the next. Fan blades range in length from 24 to 60 inches from tip to tip.Click to see full answer. Similarly, it is asked, how do I measure ceiling fan blades?Ceiling fans are measured by the full size of their blade span (also called blade sweep), which is the diameter of the circle that you see when the fan blades are in motion. Or, in other words, fan blade span reaches from the tip of one fan blade to the tip of the blade directly across.Also Know, can you replace the blades on a ceiling fan? After purchasing your new ceiling fan blades replace your old blades with them by reattaching them to the ceiling fan motor just as you removed the old fan blades. The new ceiling fan blades should simply reattach with the same screws the held your old blades in place. Considering this, how long are the blades on a 52 inch ceiling fan? Most replacement 52″ blades are around 20.5″ inches in length. Reason why is that when the blades and fan are installed, the 52″ are the final width of the fixture. It’s like measuring the wingspan of a bird, the body is included. As for the smaller 42″ size, these blades are typically is 16.5″ in length.Do the number of blades on a ceiling fan matter?Fan blade size and the number of fan blades do matter. Having fewer blades or smaller blades may reduce drag but may also generate little airflow. But increasing the blade size or fitting more blades to a fan may not necessarily generate more airflow because of the larger drag.