Up to age 4 or 33lbs and from when your child can hold their head comfortably, mines have been from about a year old maybe a bit younger. I did alot of reading up and this one came out as being the best recommended, I do like the idea of the rest for sleeping and the bairn being up front and inside my arms. TK gave me one of the rear mounted seats and it was great, the only thing I found myself doing was trying to look round to see what she was doing and when she fell asleep she was like a rag doll in the back, this gets round both of these maladies.