Ceiling Fan Size Calculator
Find the right ceiling fan blade span for any room.
Returns recommended diameter from 42 to 60 inches based on room square footage and ceiling height.
How to Choose Ceiling Fan Size for a Room
A ceiling fan that’s too small won’t effectively circulate air; one that’s too large creates uncomfortable drafts and wastes energy. Proper sizing is based on room square footage (or square meters).
Room Area Formula:
Area = Length × Width
Fan Blade Span Selection Guide:
| Room Size (m²) | Room Size (ft²) | Blade Span |
|---|---|---|
| Up to 7 m² | Up to 75 ft² | 76–91 cm (30–36") |
| 7–14 m² | 75–150 ft² | 107 cm (42") |
| 14–20 m² | 150–216 ft² | 122–132 cm (48–52") |
| 20–35 m² | 216–375 ft² | 137–152 cm (54–60") |
| 35+ m² | 375+ ft² | Multiple fans or 183 cm (72") |
Worked Example: Master bedroom: 4.5m × 4m = 18 m² → Choose a 122–132 cm (48–52 inch) fan.
Airflow (CFM) Rating: Higher CFM = more air moved per minute. For effective cooling:
- Small rooms (7–14 m²): 2,000–4,000 CFM
- Medium rooms (14–25 m²): 4,000–6,000 CFM
- Large rooms (25–40 m²): 6,000–9,000 CFM
Installation Height: Fan blades should hang 2.1–2.4 m (7–8 feet) above the floor for optimal circulation. For 2.7m+ ceilings, use a downrod extension to drop the fan to the proper height. For low ceilings under 2.4m, use a flush-mount (hugger) design.
Seasonal Direction:
- Summer: counterclockwise (viewed from below) — pushes air straight down
- Winter: clockwise at low speed — pulls cool air up and pushes warm air down from ceiling
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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