Air purifier tool
Air Purifier CADR Calculator
Estimate the minimum CADR you should compare before buying an air purifier for a bedroom, office, nursery, or living room.
How I would use this before buying
Use this before opening purifier reviews. It gives you a simple baseline so you do not buy a purifier that is too small for the room.
ENERGY STAR sizing guidance uses a simple pattern: about 65 CADR for each 100 square feet at an 8-foot ceiling. Higher ceilings usually need more.
Estimate minimum CADR
Use this before opening purifier reviews. It gives you a simple baseline so you do not buy a purifier that is too small for the room.
Useful official and authority references
These are the outside references I would keep open while using this page. They help verify rules, safety notes, return details, and shopping protections before a purchase.
Last updated May 17, 2026. Always confirm the current Amazon listing, seller, return terms, price, included accessories, and official rules before buying.