The beginner's guide to buying a car seat - from birth

Choosing the right car seat is one of the most important baby product decisions you'll have to make. The first car seat is likely to carry your baby on that all-important first journey from hospital to home. It will also ensure that your baby's journey through the first nine months of life is a safe and smooth ride, so it's really worthwhile making sure you're considering the right things when deciding which make and model to buy...

Safety
Your newborn needs to travel in a rearward-facing car seat (and should not move to a forward-facing one until he weighs 9kg and can sit up unaided). And you need a rearward-facing seat with an E Mark on it (confirming that the seat conforms to all the officially required safety standards). You may also want to consider a car seat that has additional side-impact protection.

We do not ask members who review car seats to rate them for safety, as – thank goodness – most people do not get to test this particular feature first-hand. However, we would encourage members to check the latest safety reports and contact the manufacturer direct if they have any specific safety concerns.

But it's not just about choosing a safe car seat; it's also about finding out if that seat fits safely into your car. You could buy the most rigidly protected, safety-feature-tastic car seat in the whole world and it still might not keep your baby safe in a crash if it's not fixed into your car correctly. And, most annoyingly, not all child car seats fit all cars correctly.

Many car-seat manufacturers do now provide a list of car models their seats will fit into but the only sure way to be certain is to try the seat out in your car yourself – as one Mumsnetter recently found out:

"Although we checked with a number of manufacturers first, we were amazed how many seats from the 'OK list' were actually not a great fit for our Nissan Primera. Some of the models were incredibly difficult to install because our seatbelt didn't seem long enough and others, once fitted, wobbled precariously because the shape didn't seem to fit with the shape of our car's seats."

Most retailers should let you try before you buy (if they won't, insist that they allow you to return the car seat if it turns out not to fit) and the best ones will actually help you put several in your car and advise you which ones fits best.

Weight categories
If you thought the safety stuff was complicated, you ain't seen nothing yet! There are different car seats for differently sized babies but, for some reason known only to nerdy car-seat design engineers, child car-seats are categorised into groups by numbers and symbols, rather than by weight of the baby they should contain.

Your baby's first car seat should be either a Group 0 or a Group 0+ (the 0 will fit your baby from birth to 9kg; the 0+ will be a bit pricier but will fit your baby until he's 13kg). You may also see some seats that are classified as Group 0+/1: these are 'combination' seats that can be adapted to change from rearward-facing to forward-facing once your baby's got bigger, and so fit children from birth to about four years (but, deal-breakingly for some parents, these seats can't be taken out of the car).

Portability
This will be particularly crucial in the early months when you spend your life lugging the car-seat-plus-baby bundle from car to house. (Unless you've plumped for a Group 0+/1 combination seat, in which case you'll just be lugging a baby bundle on its own.) Be warned that, however light the seat may seem in the shop, once there's a child in there, it gets heavy – and heavier as the months go on. So look out not just for a lightweight model but one that's comfy to carry, as well. (It won't matter that it's as light as a feather if you're constantly battering your legs with it!) Look, too, at the handles: some styles have ergonomic handles for easier carrying.

Ease of installation
The first time you fix a car seat into your car, you'll probably feel like a contestant in The Krypton Factor. But don't let this put you off. According to Mumsnet reviewers, some styles are tricky to install at first but "fine with a bit of practice" (check out the ease of installation ratings in our Car Seat reviews). And remember:

"It's essential to have a trial run at installing the car seat before the trip home from hospital. Although it's easy enough when you're well-practised, it takes a bit of getting used to – and it can be particularly stressful when you're the (understandably) over-anxious parents of a newborn and it's freezing cold outside."

Alternatively, you could just smile smugly at the seat-belt-routing strugglers and buy a seat that comes with a special click-on base: once you've got the base fitted in your car, you just click the car seat onto it each time – no belts or buckles to faff with (except the ones around your baby, of course!).

Comfort
The car is usually the one place you can rely on your baby sleeping but some car seats do have the edge in comfort and so may make a good snooze even more likely. Head support is essential for a newborn, so do check your seat has a head hugger/newborn insert, which can be taken out as the baby gets bigger. Some car seats have buttons/levers you can press which allow your baby to lie flat; others offer varying amounts of padding, aprons and padded wings.

Value for money
Remember that, depending on the seat you choose, you could be changing it four times between birth and age 11, so it's worth keeping an eye on cost/value for money.

But it's really not wise to buy/accept a second-hand car seat, unless it has a E mark and its original fitting instructions and you're certain it's never been involved in an accident. Any previous accident (however small) could weaken the car seat's effectiveness should you then be involved in an accident yourself. Obviously, if your sister has a 'from birth' car seat, and you know it's never been in an accident, that's fine, but this is not the sort of item you should be picking up at a car boot sale.

Special features
Car seats range from the basic and pared-down to super-duper with (almost) bells on. Think carefully what special features will actually be useful (such as gauges to tell you you've installed the seat correctly or 'one-pull' harnesses for less fiddly child-insertion) and what are just nice but non-essential extras.

Many parents like using their car seat as a 'baby chair' in the house (though babies shouldn't be left in a car seat for hours and hours), in which case it might be worth finding one that will rock – great for soothing a fractious child. Other car seats come as part of a travel system, clipping neatly onto a pushchair chassis so you can transfer a sleeping baby from car to pram without lots of snooze-disturbing lifting and unstrapping.

Car seats and the law
According to the car-seat law regulations that came into force in 2006, it is the driver's responsibility to check that children travelling in her car are "correctly restrained". You should know, then, that:

It is illegal to travel with a child under three in your car, unless the child is strapped into car seat that is suitable for her size. The only exception to this rule is travel by taxi or licensed hire car where there is no appropriate child restraint available (and, in which case, the child must travel in the rear of the car).
It is illegal to place the car seat of a child under three on a front passenger seat where there is an active frontal air bag fitted. (If you can de-activate the frontal air bag – and have done so – then that's fine.)

The legal regulations are slightly different for children over the age of three (find them here) but all children must still travel in an appropriate car seat until either their 12th birthday or they are 1.35m tall.