How to Measure for the Right Size Ceiling Fan

Measure the length and width of the room where the fan will go. Use a tape measure.

Multiply the length times the width to get the room's square footage. If a room is 10 feet wide by 15 feet long, it has 150 square feet.

Determine fan blade size. For a room with 80 square feet, a 32-inch blade fan will work to circulate air. A room with 80 to 120 square feet will benefit from a 42-inch blade. For a 120 to 144 square foot room, a 44-inch blade is recommended. Rooms with 144 square feet and greater should use a 52-inch blade fan.

Decide where the fan will go in the room. The center of the room is the ideal choice for greatest air circulation. Consider obstructions and objects within the room when selecting the location.

Calculate ceiling-space requirements for the fan to operate safely. For a fan with 52-inch blades, this is more than 104 inches (52 inches per blade x 2 blades on each end) because the motor housing needs to be considered. Motor housings may be a foot or greater in width. The fan would need at least 116 inches or almost 10 feet of space (104 inches + 12 inches).

Consider the fan height. A fan is either flush mount where it is attached against the ceiling or it uses a downrod. For optimum air circulation, fan blades should be 8 to 9 feet above the floor.