Result
116 CADR or higher
A 1440 cu ft room needs about 116 CADR for 4.8 air changes per hour.
- Room volume
- 1,440 cu ft
- Target CADR
- 116
What CADR means
CADR is clean air delivery rate. Higher CADR means the purifier can clean more air per minute, which matters more as room volume increases.
Choosing air changes
Bedrooms often feel comfortable around 4 to 5 air changes per hour. Allergy or smoke situations may benefit from a higher target.
Formula and assumptions
This calculator uses the inputs above to turn a practical planning question into a usable estimate. The result should be treated as a starting point, because product ratings, room conditions, material waste, and real-world use can vary.
Example calculation
Example inputs: Room length: 12 ft; Room width: 15 ft; Ceiling height: 8 ft; Air changes per hour: 4.8 ACH. With those values, the calculator returns 116 CADR or higher. A 1440 cu ft room needs about 116 CADR for 4.8 air changes per hour.
Common planning mistakes
Avoid using rough guesses for every input, forgetting waste or safety margin, and treating the estimate as a guaranteed final number. Measure the space, round up when buying materials or equipment, and compare the result with product labels or project instructions.
FAQs
Air Purifier Size Calculator questions
Can I use one purifier for multiple rooms?
Only if air moves freely between the rooms. For best results, size the purifier for the room where it will actually run.
Should I round up?
Yes. Rounding up gives you more fan-speed flexibility and can help keep noise lower.