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
State
$ Cost/kWh
Hours/Day
Days/Year
w/Lights ON
$0.0021/hour	$18.7/year

(Instructions/Details)

Basic Help: Our operational cost calculator estimates how much it will cost to operate the {{var name}} ceiling fan. By default, the calculator assumes that you will leave your fan running 24 hours a day for the entire year (which is not very likely to be accurate), so you will want to change the hours and days to be more in line with how often you think you will use the fan. The calculator also defaults to the average cost per kWh of electricity in the USA. You can change this to use the average cost of electricity in your state, although this may vary widely from city to city. For the most accurate calculation, manually enter the actual cost/kWh shown on your utility bill. The wattage of the fan is already included (if it is known), but you can change it if you wish to see how the wattage affects the cost.

Fans with lights: Calculations are performed without lights by default. If you add a light fixture to the fan, you can add the wattage of the fixture to the wattage of the fan to perform calculations with the lights on. In some cases, when a light fixture of known wattage is included with the fan, the option to calculate with or without lights will show automatically. The light fixture on a ceiling fan almost always uses substantially more electricity than the fan motor, so it is very important to take that into account when comparing the overall operational cost between various ceiling fans

CFM -vs- Efficiency: CFM is KING! It is more important to buy a fan with higher CFMs than it is to buy a fan that uses less electricity. The highest wattage consumed by the most energy guzzling ceiling fan on our website is about 120 watts. So if you input 120 as the fan watts and run our calculator, you will see that it still costs less than 2 cents per hour to operate the most energy guzzling ceiling fan in most states. You will get more savings with a higher CFM fan than a lower Wattage fan because if your fan moves more air you will be able to raise your thermostat to a higher degree. Raising your thermostat by 10 degrees can save you up to 40% on your cooling bills. Choosing a less powerful fan because it uses less electricity can be the worst mistake you can make because it will not cool you off enough to allow you to raise your thermostat to a high enough level without becoming uncomfortable. This is why CFM is so much more important to consider than Wattage.

When comparing fans of different sizes with varying CFMs, it is important to consider the wind speed in order to know which fans will make you feel cooler. Read more about Ceiling Fan Wind Speed here!

The average kWh by state used by our calculator is derived from information published by the US Government Department of Energy as of May 2009. Your actual cost may differ from this. Again, refer to your utility bill for your most recent kWh cost.

Ceiling Fan Wind Speed Factor Calculator

Blade Span
CFM
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
Calculate
Max RPM (1/8" Thick Blades)	176.29
Max RPM (3/16" Thick Blades)	235.06