How to Measure Your Space for the Perfect Ceiling Fan

Not all ceiling fans are created equal. In addition to coming in different shapes and styles, ceiling fans importantly come in a large number of sizes — and those sizes have very specific applications. Unlike other types of home décor, ceiling fans have important functionality: moving air around the space to improve comfort. If a ceiling fan is too small, it will have a negligible impact on air movement. In contrast, if a ceiling fan is too large, it may take up too much headroom, dominate sight lines or perhaps even do damage to other elements in the space.

Before you invest in a ceiling fan, you need to know that you are buying a fan that is the exact right size. Here’s a guide for measuring your space and choosing a ceiling fan that looks and works perfectly.

Measure the Space’s Square Footage and Height

The first and most important measurement you need to take before purchasing a ceiling fan is the square footage of your space. Square footage is calculated by finding the area of flooring in your space. Square footage is easiest to calculate in rooms that are simple rectangles, as you will measure the length of the room and the width of the room, then multiply both measurements together. If your room has small alcoves or niches, as around a fireplace or between windows, you do not need to worry about factoring them into your calculation; the main length and width of the space should suffice to find the right fan. Additionally, you can round up or down to the nearest inch, as these measurements are merely rough guides for ceiling fans and do not need to be perfectly accurate.

The measurement becomes more difficult if your room is a compound shape — if two rectangles are jointed into a large open area or if additional shapes, like circles or triangles, are contiguous, you might need to perform more complex math. You should separate your space into different shapes, using blue tape to mark out where each shape lies. Then, you can calculate the area of each different shape, adding those figures together to create your total square footage. Again, you don’t need to worry about small bumps or recesses; they are negligible and do not affect the perceived size of the room.

While you have your measuring tape out, you might want to measure the height of your space, as well. Ceiling fans should be hung at a proper height to ensure that the fan has a noticeable effect on airflow but to prevent anyone from bumping their head or hands on the rotating blades. Fans should be no closer to the ground than 7 feet, but they should not exceed 9 feet from the floor.

Once you have a relatively accurate measurement of your space’s square footage and height, you can consult the following list to find the right-sized fan:

Spaces under 144 square feet: fans smaller than 42 inches. These rooms are most often bathrooms, breakfast nooks, utility rooms and small bedrooms.

Spaces between 144 and 225 square feet: fans between 44 and 50 inches. These tend to be medium-sized bedrooms and typical communal spaces, like kitchens, dining rooms and dens.

Spaces between 225 and 400 square feet: fans between 50 and 62 inches. These rooms are often primary bedrooms, family rooms and small garages.

Spaces over 400 square feet: fans larger than 62 inches. These spaces tend to be cavernous, which is why they warrant the installation of large ceiling fans. They include great rooms, large garages and basements.

In long, thin spaces with large square footage, it might be wise to invest in multiple smaller fans, which will be more effective at moving air. In any case, you should never hang a ceiling fan closer to the wall than 18 inches, as doing so reduces air flow.

Understand Ceiling Fan Measurements

So, now you know what size fan you should install in your space — but how do you know which fan is the right size? The fan sizes listed in the chart above apply to the blade span of the fan, which, frustratingly, is calculated in different ways for different fans.

Specifically, the number of blades on your fan will determine how you measure the span. If you are looking to buy a fan with an odd number of blades, the blade span is calculated by measuring from the center of the fan along the length of one blade and multiplying by 2. If you are interested in a fan with an even number of blades, you will measure from the far edge of one blade through the center of the fan and to the far edge of the other blade — in other words, you are taking the fan’s diameter.

You can usually find the blade span within the descriptions of ceiling fans online or posted on the exterior of ceiling fan boxes. However, if you notice that your current fan is not efficiently affecting the temperature of your space, you may want to measure the span and replace it with a fan of the correct size.

With these tips in mind, you can install the perfect ceiling fan to complement your space.