Car seats are usually labelled by weight with an age-range as a rough guide. Let your child's weight be your guide of when to
move up to a bigger seat as some children are smaller than others and may benefit from staying in a car seat longer than bigger children
of the same age. At the older end of the range, their height is an important factor and they should remain in a booster seat or cushion until they are over 135cm.
Rear-facing seats for children weighing up to 13kgs. This is from birth to a maximum age of nine to 12 months (but quite probably younger).
Forward-facing (some rear facing seats can safely be turned round, where this is clearly stated) seats for children weighing from 9kgs to
18kgs. This is from about nine months to four years.
These integrate the adult belt into a seat with good support for the child's body (and preferably head). These are suitable for children
weighing between 15kgs and 25kgs. This is about four to six years of age.
These are what they say, really. They will lift the child up so the adult seat belt cuts across their body more comfortably. These are
suitable for children from six years of age. These should be used until your child is over 135cm in height, after which time, an adult belt may be used.