There may be a number of reasons why your cat may be purring all the time. First of all, this is usually a sign that cats feel content and comfortable, especially when they are petted, fed, or nursed by their owners. This sound is made by vibrating falsetto and resonating through the throat cavity. It is a way for cats to express contentment and relaxation.

However, cats may also purr when they feel anxious or upset. This usually happens when the cat is in a new environment, facing unfamiliar people, or is scared. This purring may be the cat trying to relieve himself from stress.