Choosing The Right Car Seat

How do you decide which car seat is right for you?

The choice can be quite overwhelming and it can be difficult to know which seat to choose. Do you buy one that fits onto your pushchair? Should it go on a base? Do you buy a bigger seat that will last longer? Should it be belt fitted or ISOfix? And when will the baby need a bigger seat? Rear or forward facing? What about booster seats?

The information on this website explains which types of car seats are available, and will hopefully make it easier for you to know what to look for. Which car seat is best for you will depend on your child's age, weight and height, the height of the driver and front passenger, whether you have other children or adult passengers, as well as your budget and of course your car.


Your baby's first car seat

Most babies' first car seat is a small seat known as an infant carrier. These seats go up to 13kg or 75-87cm. One of the advantages of an infant carrier is that you can carry the baby to and from the car in the car seat. Most of them can be used on a pushchair chassis and a lot of brands use the same adapters, so you can often mix and match your favourite car seat with your favourite pushchair.

Infant carriers can be installed in the car with the seat belt or on a separate ISOfix (or belt fitted) base. Having a base is very convenient, as it stays in the car and the seat can be clicked in and out of it in seconds. You will probably also find that your baby can use the seat for a few months longer on a base, because when you install the car seat with the seat belt, the lap belt goes over the baby's legs and some older babies find that annoying.
There are a few i-Size infant seats that come with a base and cannot be installed without it, but for most car seats the base is an optional extra. You may decide that you don't mind installing the seat with the seat belt every time, and don't want the extra expense of a base. Or occasionally the base may not be compatible with your car. Installing an infant car seat with the seat belt is quick and easy, and just as safe as using it on a separate base.

Another option is to buy a car seat that is suitable from birth to 18kg or 105cm, which will last for about four years. These stay in the car and can't be carried or used on a pushchair. And there are currently three car seats available in the UK that rear face from birth all the way up to 125cm.


Bigger car seats for older children

Car seats for older children come in two weight/height limits and will last up to either four or six years on average. A seat with a 25/36kg or 125cm limit will last at least two years longer than one that goes up to 18/22kg or 105cm.

You can't predict how heavy your baby will be before they're born, but by the time they need a new car seat at around 15 months, you will know if they're big or small for their age. The average age at which a child reaches 18kg or 105cm is four and a half to five, but all children are different and some can be as young as two, others as old as six. For those on the higher percentiles it's particularly important to get a car seat that rear faces up to 125cm, because they will outgrow a 105cm seat before they're four years old and that is not old enough to move up to the next stage. We encourage everyone to keep their children in a rear facing seat up to 125cm until they no longer fit.

But that doesn't mean that we don't recommend car seats up to 18kg/105cm. Extended rear facing seats that go up to about four years are often the only option for a second child if the first is already in a 125cm seat behind the front passenger seat, and a second large seat won't fit behind the driver. Or some people choose to buy an 105cm seat when their first child is one, knowing that they will eventually buy them a bigger seat when a future sibling needs the smaller one. If the car is small and the parents are very tall a seat up to 105cm may be the only one that fits. And for people who don't own a car but need a seat for taxi rides and lifts with friends and relatives, a lightweight belt fitted seat up to 18kg/105cm is the most practical option.

If you choose an infant carrier as the first car seat, you will need to buy a bigger one when your baby is roughly 12-18 months old. There are lots of different types available. Most now rear face up to at least 105cm, but there are still quite a few available that face forward from 76cm or 15 months. Legally a baby can face forward from 9kg (approximately nine months) in an R44/04 seat, or from 15 months in an R129 one (please see the regulations page for more information).

We don't recommend using a forward facing car seat under the age of four, because in the event of an accident a forward facing child is five times more likely to be seriously injured than a rear facing one. Therefore we encourage all parents to keep their children rear facing until they are at least four years old, preferably longer.


Seat belt or ISOfix?


Car seats that go up to 25/36kg are always belt fitted and tethered, but up to 18kg/105cm you can choose a belt fitted seat or one that clicks into the car's ISOfix points. A correctly installed belt fitted rear facing seat is no less safe than an ISOfix one, but ISOfix seats are quicker to install. This may be a factor if you are using the seat in more than one car and need to move it regularly. Most ISOfix car seats up to 105cm swivel towards the door which can be useful when strapping the baby in.
There are currently two ISOfix car seats available in the UK that go up to 125cm and I expect that we will start to see more of them in the coming years.

At around 15kg ISOfix seats are quite heavy, and if you need to move the seat often you may want to consider one with a separate ISOfix base. The seat and the base only weigh 7 or 8kg each and are easier to carry than an all-in-one seat. Belt fitted seats up to 105cm/18kg don't weigh more than 9kg.

If you are using two or more cars and not all of them have ISOfix points, you will have to choose a belt fitted car seat that can be used in every car. ISOfix is nice, but just because your car has it doesn't mean you have to use it, and in some circumstances a belt fitted seat is a better choice. Belt fitted seats up to 18kg can be a lot cheaper than ISOfix ones.


High back booster seats

Once the weight or height limit of your child's harnessed car seat has been reached it is time for a high back booster. These belt positioning seats can be used from 100cm or 15kg, but as there are harnessed seats that can rear face up to 125cm or 36kg, it is safer to delay using a high back booster for as long as possible.

A booster has three jobs. It needs to lift the child up so that the lap belt lies on the hips and not on the soft abdomen, it needs to position the diagonal belt correctly across the chest and shoulder, and the backrest needs to keep the child upright, even when they're asleep.

A child must be AT LEAST four years old before going into a high back booster, even if they reach 15kg or 100cm sooner. Before the age of four they are not physically mature enough for the adult seat belt to protect them in a crash, and not mentally mature enough to sit still for the entire journey and not play with the seat belt.

If you have ISOfix points in your car, choose a booster seat that can be connected to them. Some boosters have straps with hooks and others have rigid arms. Booster seats that are connected to the car's ISOfix points are more stable in the car and you won't have to remember to strap them in when the child is not with you. If your car doesn't have ISOfix or the seat has to go in the middle seat which usually don't have ISOfix points, the booster's ISOfix arms can be stowed away inside the seat.


Convertible Car Seats

There are a few car seats that start off as a rear facing seat and can be converted into a high back booster (from 100-150cm or 15-36kg) later on. This may seem like a good idea, these seats are usualy advertised as being suitable from birth to 12 years so they can be used for a long time. But they all have a rear facing harness limit of just 105cm and the product descriptions don't always make that clear. It is much better to rear face up to 125cm and then buy a high back booster when the rear facing seat is outgrown.
However, these combination seats can be useful for a second child when the older sibling is already in a bigger rear facing seat. The younger child can then rear face in a convertible seat until both children are ready to move up and then they can simply swap seats, so that the youngest can continue to rear face and the convertible seat can be used as a booster for the older child.