Hi! My son is 42 lb and almost 5 and tall for his age, he's fine and still has a ton of room to grow, this is to hold up to 85 lbs/57" and converts to a booster w/ seatbelt use, to hold up 120lbs/65".... We got this one bc it will last the longest, we love it and bought another for our youngest.... Hope this helps!! :)
I agree completely with mamabk. I have one for our 4 year old, and he has plenty of room. I am very happy with it and bought one for our 2 year old. I has a bit of a wierd angle and does not fit well in an older buick I tried to put it in, but if it does not fit in you car, amazon is wounderful to return to.