How to Measure Fan Size

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Updated July 21, 2022

If you are new to the world of indoor cooling, you may wonder how to measure a fan. The best fans, after all, still need to fit inside of your home. So why measure a fan, and how to conduct all of the necessary measurements to successfully place a fan (or three) in your space? Keep reading to find out.


  • Measuring a fan is useful for room placement and for deciding what type of fan to purchase for your space.
  • Before measuring any size ceiling fan, measure the room it will live inside. Do this with a simple tape measure to assess the square feet metric. Ceiling height and cubic feet could be trickier.
  • Measure ceiling fan size by taking a tape measure from the tip of one ceiling fan blade to the tip of its opposite blade.

Why Measure a Fan’s Size?

To understand how to repair a fan, such as when learning how to fix a stand fan, it is helpful to know the appliance’s various dimensions. Beyond that, knowing a fan’s size is helpful for placement, like when you learn how to position fans to cool a room. It is also helpful when sourcing replacement parts and when measuring efficacy, such as when you wonder how many CFM a box fan is.

Insider Tip

No matter how you decide to measure your fan, make sure to clean the blades to ensure efficiency.

How to Measure Fans

There are a number of different fans out there, so let’s go through all of the major players. However, before you measure any fan, you need to measure the room you are placing it inside.

Measuring a Room

The easiest way to measure a room is simply to take a tape measure and travel from corner to corner, marking down each measurement as you go. Take a tape measure from one wall to the opposite or length, and then do the same for width using the remaining walls. Multiply the length times the width to suss out the room’s total square footage. For instance, a 12- by 15-foot room will have a square footage of 180 feet.

Measuring a Ceiling Fan

You may need to measure the diameter, or sweep, of your ceiling fan before placement or to tell a repair expert. Start by powering down the fan and allowing the blades to come to a complete stop. Grab a ladder and a tape measure and head up to the fan blades. Tape your tape measure and extend it from the tip of one blade to the exact opposite blade on the other side of the fan. This is your fan’s diameter.

Measuring Tower and Pedestal Fans

You likely won’t have to measure these fans, as they fit in just about any room. Still, if you want an exact measurement for decorating purposes, this is how you do it. Take your tape measure from the bottom and string it to the top. That is your fan’s height. The diameter can be tricker, depending on how many exuding components. Check the instructions or box for more information.

STAT: If your room has an “L” shape, simply divide the room into two rectangles. Determine the square footage of each rectangle by the above method and then add those results together. (source)

Measuring Fan Size FAQs

How to determine downrod length?

Measure downrod length by using a tape measure to go up and down the rod. Most ceiling fan manufacturers use similar lengths here so as to not place stress on a ceiling joist.

How to use your measurements to select a fan size?

No matter the square feet of your home and the square feet metric of the fan itself, you can easily purchase the right fan by checking the dimensions on the box to ensure optimal circulation.

What size ceiling fan for a living room?

It really depends on the square footage of the living room in question and how high the ceilings are. For instance, a 10-foot ceiling could require a different downrod ceiling fan than a 12-foot ceiling.
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