Fan Size Calculator
Enter the room length, width and ceiling height. The calculator suggests the blade span, the downrod length to put the blades at a good height, the airflow in CFM and whether a long room needs two fans.
- Ceiling fan size
- Downrod length
- Airflow
Blades should be at least 7 ft above the floor and 18 in from walls.
Room size sets the blade span. A small bedroom up to about 144 sq ft takes a 36 to 44 in fan. A living room up to 225 sq ft suits 44 to 50 in, and up to 400 sq ft 50 to 54 in. On a 10 ft ceiling, a 12 in downrod drops the blades to about 8 ft.
Ceiling fan size chart
By room area. Search for a room size.
| Room (sq ft) | Blade span (in) | Airflow (CFM) | Room example |
|---|---|---|---|
| Up to 75 | 29 to 36 | 1,000 to 3,000 | Bathroom, laundry |
| 76 to 144 | 36 to 44 | 1,600 to 4,500 | Bedroom, office |
| 145 to 225 | 44 to 50 | 2,300 to 6,500 | Living room |
| 226 to 400 | 50 to 54 | 2,800 to 7,000 | Large lounge |
| Over 400 | 56 and up | 4,000 to 9,000 | Open plan |
Airflow in cubic feet a minute.
Room size and fan
9 ft ceiling. Slide the room area.
The side view shows the fan, its downrod and its blade sweep.
How to choose a ceiling fan
Room to fan. Step through it.
Measure the room
Length × width.
Check the ceiling box is rated for a fan, as fans need stronger support than lights.
Flush, standard or long downrod
Mounting. Compare them.
Low ceilings.
Most rooms.
High ceilings.
Sloped ceilings need an angle adapter as well as the right downrod.
Before you buy
Fan checks. Tick each item.
Tick each item as you go.
Fans move air but do not cool it. They work by helping sweat evaporate.
What you get
Fan sizing. Each tile explains one result.
Inches.
Span.
Room.
CFM.
Length.
Run fans anticlockwise in summer for a breeze and clockwise on low in winter to push warm air down.
Frequently Asked Questions
No question matches that search.
What size ceiling fan do I need?
About thirty-six to forty-four inches for a bedroom, forty-four to fifty for a living room and fifty to fifty-four for a large room.
How long should a downrod be?
About six inches for a nine foot ceiling, twelve for ten feet and twenty-four for twelve feet.
How high should ceiling fan blades be?
About eight to nine feet above the floor, and never under seven.
Can a fan be too big for a room?
Yes. It can feel blustery and look out of proportion.
When do I need two fans?
In long rooms or rooms over about four hundred square feet.
What is CFM?
Cubic feet a minute, the amount of air the fan moves.
Do I need a special fan for a bathroom?
Yes, choose one rated for damp locations.
A cool breeze in every room
Match the blade span to the room and the downrod to the ceiling, and the fan moves air just where you need it.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.