Ceiling Fan Size Calculator (Metric)
Find the right ceiling fan blade span for your room based on its size, so you get good airflow without overpowering the space.
What your result means
Recommended blade span is the fan diameter that moves air well for your room size without looking under- or over-sized. Too small a fan barely stirs a big room; too large overwhelms a small one. Room area is length times width. For larger great rooms, two smaller fans often beat one giant one. Need the area for other tasks? See our square footage calculator.
How to use this calculator
- Measure the room length and width in feet.
- Read the recommended blade span for that area.
- For rooms over about 37.2 m², consider two fans.
- Mount the fan 8 to 2.7 m above the floor for best airflow.
- Keep blade tips at least 45.7 cm from the nearest wall.
The formula
Fan sizing is based on room area. These blade-span ranges are the widely used industry recommendations — bigger rooms need a wider span to move air across the whole space.
Worked example
A 12 by 3.7 m bedroom is 13.4 m², which falls in the 44 to 132.1 cm range — a 52-inch fan is a solid choice. A small 8 by 2.4 m bath (5.9 m²) wants a compact 29 to 91.4 cm fan instead.
Ceiling fan size by room area
| Room area | Blade span |
|---|---|
| Up to 7 m² | 29 - 91.4 cm |
| 75 - 11.1 m² | 36 - 106.7 cm |
| 120 - 20.9 m² | 44 - 132.1 cm |
| 225 - 37.2 m² | 52 - 152.4 cm |
| Over 37.2 m² | 152.4 cm+ or two fans |
Tips & gotchas
- Mount blades 8 to 2.7 m above the floor — too low hurts both airflow and safety.
- Keep blade tips at least 45.7 cm from walls and 24+ inches from sloped ceilings.
- For rooms over 5.5 m long, two fans move air more evenly than one big one.
- Use a downrod on high or vaulted ceilings to bring the fan to the right height.
- Higher airflow (CFM) ratings matter as much as blade span for cooling feel.
Frequently asked questions
What size ceiling fan do I need?
Match blade span to room area: about 44 to 132.1 cm for a standard 120 to 20.9 m² room, smaller for baths, and 152.4 cm or two fans for great rooms.
What size fan for a 12x12 room?
A 12 by 3.7 m room (13.4 m²) suits a 44 to 132.1 cm fan, with 132.1 cm a common, effective choice.
How high should a ceiling fan hang?
8 to 2.7 m above the floor is ideal. Use a downrod on tall or vaulted ceilings to reach that height.
Can a fan be too big for a room?
Yes. An oversized fan in a small room looks overpowering and can create uncomfortable drafts. Match the span to the area.
Should I use two fans?
For rooms over about 37.2 m² or longer than 5.5 m, two smaller fans distribute air more evenly than a single large one.
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Estimates only — see our full disclaimer.