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Ceiling Fan Calculators

Updated: 8/4/2022

Here are some useful ceiling fan calculators that I have created over the past several years that are being used in various places on our website. I thought it might be a good idea to consolidate them all on a single page.

Ceiling Fan Size Calculator

This calculator is based on the current trend to use Larger fans in Smaller rooms. Based on this new trend, we recommend this: "Choose the largest fan with the highest wind speed that will fit into the space without overwhelming it visually". In rooms larger than 10 x 10, leave 2 to 3 feet from the blades to the shortest wall to determine the largest size we would recommend visually.

Select your room dimensions to the nearest foot

Room Size: X
Ceiling Height:

Angled Ceiling Calculator

Follow the diagram above to find the "Rise" of your ceiling then select a fan size.

Ceiling Rise
Fan Size
12" Min.

Shortest Downrod*
Bottom of redzone where blades hit ceiling:
Minimum drop to clear ceiling 12" vertically:
Minimum drop to clear ceiling 18" horizontally":
Ceiling Pitch:
Ceiling Slope:

Interpreting The Results

Call Us: Our ceiling fan experts know how to interpret these numbers and help you find the perfect size fan and downrod for your angled ceiling. Please call us for help at: 1-800-201-1193.

*Shortest Downrod:

This is the shortest downrod that will put the blades below the "Min. Drop" distance, which is the point where the blades clear the ceiling by 12" vertically and 18" horizontally. These clearances are recommended by most fan manufacturers to help prevent the fan from wobbling due to air bouncing off the ceiling. Downrods come in 6" to 12" increments, so it is possible the closest downrod to the "Min. Drop" will put the fan well below that mark. If you need to maximize the headroom and get the fan as close to the "Min. Drop" as possible, some downrods can be cut on the job.

Ideal Downrod Length:

For maximum efficiency the blades need to be as close to 7 feet from the floor as possibles for you to feel the most breeze. Measure from the floor to the ceiling where the fan will be mounted and deduct 80" to determine the longest downrod you can use.

7 Foot Rule:

Safety standards require the blades to be at least 7 feet from the floor. If the minimum downrod drops the blades lower than 7 feet, you may need to consider a smaller diameter fan or no fan at all.

Angled Ceiling Adapters:

Most fans come with a ball hanger system that will allow the fan to hang on a flat ceiling or angled ceiling anywhere form 15° to 33 °. For angles larger than the standard mounting hardware you can purchase an angled ceiling adapter that will work up to 45° (for most brands). Anything over 45° will require you to construct a triangular box that mounts to the ceiling allowing the fan to be installed on a flat surface. Call for help!

Estimated Calculations:

Our calculations assume the fan and mounting hardware will add 6" to the overall height from the ceiling to the blades. For a more accurate calculation, you will need to add or subtract from the 6" depending on the specifications of the fan you are considering.

Diagram Definitions

Bottom of redzone where blades hit ceiling:

The red zone in the diagram indicates the area where the fan blades will hit the ceiling. If you opt to ignore the 12" vertical and 18" horizontal clearance rule, your fan must at least drop below the bottom of the red zone.

Minimum drop to clear ceiling 12" vertically:

This is the shortest drop that will allow the blades to clear the ceiling 12" vertically.

Minimum drop to clear ceiling 18" horizontally:

This is the shortest drop that will allow the blades to clear the ceiling 18" horizontally.

Ceiling Pitch:

This is the angle of your ceiling measured in degrees. You will need this in order to determine if you need to purchase an angled ceiling adapter (Angled Ceiling Adapters above).

Ceiling Slop:

Slope is another way of defining angled ceilings. It is the ratio of the Rise and Run of the ceiling and is the main variable we use in our calculations.

Ceiling Fan Operational Cost Calculator (2022)

Operational Cost Calculator

Fan Watts
Light Watts
$ Cost/kWh
w/Lights ON

Ceiling Fan Wind Speed Factor Calculator

Blade Span
Wind Speed MPH 3.76 MPH
Wind Speed LFM 331.04 LFM

Enter the CFM and Blade Span. Read About Wind Speed Here!

Our Rating System (1-5): 1=< 1.5 | 2=1.5 to 2.49 | 3=2.5 to 2.99 | 4=3 to 3.75 | 5=3.75 to 3.99 | 5.5=4 or More

Ceiling Fan Maximum RPM Calculator

Blade Span
Max RPM (1/8" Thick Blades)
Max RPM (3/16" Thick Blades)