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Comfort · blade span and downrod

What size ceiling fan do I need?

Match a fan's blade span to your room size, and its downrod to your ceiling height, so it hangs in the 8-to-9-foot sweet spot for airflow. Both come from your room's numbers below.

Ceiling fan size calculator

blade span + downrod
A 12 by 12 room is 144 sq ft.
Where is it?
Recommended blade span n/a

Downrod n/a
Mount n/a
Rating Indoor
On airflow (CFM). There is no official "CFM per room" standard. ENERGY STAR certifies a fan's efficiency, not a target for your room. As a rough rule of thumb, a larger or warmer room wants a fan on the higher end of its airflow range; do not read a precise CFM off a chart, since the sources do not agree on one.

Before you hang it: a ceiling fan needs a fan-rated electrical box, not a standard light box, because of the weight and motion. A new or replacement box is a licensed electrician's job. We give no wiring instructions. Blade span and downrod here are industry convention, not a tested standard; nothing you enter leaves your browser.

The method

Span from the room, downrod from the ceiling

Blade span comes from floor area. The long-standing guide, from the American Lighting Association and repeated by Energy Star, runs from a 29 to 36-inch fan for a small room up to a 50 to 54-inch fan for a room near 400 square feet. Past that, one fan cannot move air evenly and you want two.

Downrod comes from ceiling height. An 8-foot ceiling takes a flush or hugger mount with no rod. Higher ceilings need a downrod to bring the fan down to about 8 or 9 feet off the floor, where it actually moves air on you. Energy Star gives the endpoints; the lengths in between are convention, so treat them as a starting point.

Questions

Common questions

What size ceiling fan for a 12x12 room?

A 12 by 12 room is 144 square feet, which puts it right at the top of the 36 to 42-inch band. A 44-inch fan is a safe pick for a room that size. Bedrooms and offices in that range do well with a 42 to 44-inch span. Enter your exact square footage for the band it lands in.

What size ceiling fan for a bedroom?

Most bedrooms fall between 120 and 225 square feet, which calls for a 42 to 44-inch fan. A small bedroom under 144 square feet can take a 36 to 42-inch fan; a primary bedroom over 225 square feet moves up to the 50 to 54-inch range. Measure the room and match the band.

What downrod length for a 10 foot ceiling?

For a 10-foot ceiling, a downrod in the neighborhood of 12 to 18 inches drops the fan to the 8-to-9-foot sweet spot for airflow. An 8-foot ceiling takes no downrod at all, only a flush or hugger mount. These lengths are convention, anchored to Energy Star's guidance to hang a fan 8 to 9 feet off the floor.

Do I need a special fan for a patio?

Yes. A covered porch or patio needs a damp-rated fan, and a fully exposed spot that can get rained on needs a wet-rated one. A standard indoor fan will corrode and fail outdoors. The calculator flags the rating when you set the location, but always check the fan's own damp or wet rating before you buy.