Air Purifier Room Size Calculator
Match an air purifier to your room size. The key spec is CADR (Clean Air Delivery Rate) — too small and it can’t keep up with a room’s air volume.
Air Purifier Room Size Calculator
Find the CADR (Clean Air Delivery Rate) an air purifier needs for your room.
Your recommended CADR rating will appear here.
Minimum CADR
—
general use (CFM)
For allergies / smoke
—
higher air changes (CFM)
Based on air-change targets (about 4.8 air changes/hour for general use, 6+ for allergies). This tool provides a rough estimate for general informational purposes only and is not professional advice, a guarantee, or a quote. Results may not reflect your specific situation. Always confirm with a licensed HVAC professional before making any purchase or decision. See our Terms of Service for details.
Frequently Asked Questions
What CADR do I need for my room?
A common rule (AHAM 2/3): the purifier’s CADR in CFM should be at least two-thirds of the room’s area in square feet. A 300 sq ft room needs roughly 200 CADR or more.
Where should an air purifier go?
Place it in the room where you spend the most time, away from walls and furniture so air can circulate freely through it.