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Baby & child.

22 June 2021

Baby vs child car seats: what's the difference?

Babies need specific protection in a baby car seat. Find out what to look for to help keep your little one safe when travelling.
Alison Potter
Newborn baby in car seat

Baby car seats are, as the name suggests, suitable specifically for newborns and younger babies. 

Child car seats, on the other hand, are designed to protect children's soft bones and vulnerable internal organs at each stage of development, from birth to the age of 12 or when they reach 135cm tall. 

But newborn babies need different levels of protection from toddlers and older children. So you need to make sure you're getting a car seat that's suitable specifically for younger babies, to ensure they travel in the best position and are supported all the way.

To find out which seats we recommend, see our car seat reviews or go to our pick of the top 10 best baby car seats.

Video: How to put a newborn baby in a car seat

Watch our video below for a step-by-step guide to putting your baby safely in an infant car seat. 

How does a newborn car seat protect your baby?

To reduce the risk of injuries to your baby in the event of a crash, a newborn car seat needs to:

  • make sure your baby’s head doesn't move around, which causes the neck to stretch
  • stop the head banging into other surfaces, such as the front seat or car door
  • surround your baby with a protective shell to prevent them being hit by bits of car or debris
  • distribute the pressure from the child restraint as widely as possible over the strongest parts of the body, such as the back.

The best way to help keep your baby safe in a car crash is by keeping them in a rear-facing baby car seat for as long as possible. At a minimum 15 months, but ideally until your child is three or four years old. 

Just over half of the 2,021 parents we surveyed in February 2021 thought it was safest for babies to travel forward-facing in a car seat rather than rearwards, but actually the opposite is true.

This is because in a front impact (one of the most common types of crash), a rear-facing seat pulls the child into it, cushioning the head and back and limiting the movement of the head or the neck.

Compare the best and worst rear-facing child car seats

  • Find out which baby car seats sailed through tough crash tests – browse the best child car seats
  • Discover which car seats we've labelled with a safety alert, and the reasons why, in our guide to Don't Buy child car seats.
car crash

Why does a baby need the right size car seat?

When babies are born, their bones and muscles still have a lot of growing and strengthening to do. They're particularly vulnerable to injuries caused by impact and uncontrolled movements of their head.

The head, neck and spine

The head is large and heavy in comparison with the rest of a baby's body, accounting for about a quarter of its total length and about a third of the weight.

The neck muscles are weak, and unable to lift or control the movement of the head.

Bones in the infant spinal column are held together quite loosely by weak ligaments. This makes it fairly elastic, allowing it to stretch up to 5cm. But the spinal cord will snap if it's stretched too much, which can be fatal.

crash test rig set up with dummies

The skull

The skull bones are separated by membrane-filled spaces that slowly grow together, but are not fully fused until 18-24 months after birth.

This means that a baby's skull is very flexible – relatively low impacts can result in significant deformation of the skull and brain. The smaller the child, the lower the impact needed for injury.

The chest and pelvis

A baby’s ribcage is very flexible, too. An impact to the chest can result in the chest wall squashing on to the heart and lungs.

The ribcage isn't well developed, and can't protect some of the abdominal organs.

The bones in the infant pelvis aren't fused together strongly like an adult's.

These things mean an infant's chest and pelvis can’t absorb strain from a restraint without the risk of injury to the internal organs, which is where a good baby car seat comes into its own. 

A well-designed seat will cushion your baby in the event of a crash, and help to divert the crash force away from your baby's body.

newborn in car

Find out how our car seat crash testing goes beyond the legal regulations to check if your car seat can protect your baby.

Video guides: how to fit a rearward-facing baby car seat

To make sure you know how to fit your child car seat correctly, we've created a handy video guide that walks you through fitting your child's very first child car seat.

Lie-flat baby car seats and carrycot baby car seats

Experts agree that the safest way to transport babies is in a rearward-facing infant carrier or baby car seat. A good baby car seat will help to protect your baby in both frontal and side-impact crashes.

However, lie-flat or carrycot car seats can be a good solution for newborns, especially premature babies or those with medical conditions, who need to be transported lying flat.

Models we've tested include the  Maxi-Cosi Jade + 3wayFix, Joie i-Level, Jane Matrix Light 2 and Britax Romer Baby-Safe2 i-Size

Some carrycot car seats are suitable only for babies up to 10kg, which means parents might change to a forward-facing next-stage seat too early. 

Our advice would be to look out for a modular system – one that uses a base which is also compatible with a rear-facing baby car seat and then a rear-facing toddler seat. 

For example, the Maxi-Cosi Jade can be installed into the 3wayFix Isofix base, which you can also use with the Maxi Cosi Pebble Pro i-Size and Maxi Cosi Pearl Pro i-Size car seats.

It's considered safest to keep your baby in the lowest-group car seat until they reach the weight limit, or outgrow it.

carrycot vs child car seat

Fitting advice for carrycot car seats

If you're using a carrycot car seat, you should:

  • place it across the back seat, as close to the middle as you can. This may use up more space, but it means your baby is less vulnerable in a crash
  • place your baby’s head as far from the door as possible, to try to avoid contact with the door in a crash.
baby in car seat