What kind of car seat does a newborn need?

A newborn needs a rear-facing seat used in the back seat. Most parents start with a rear-facing-only infant seat, which has a carry handle and a base that stays clicked in the car. A convertible seat that starts rear-facing also works as long as it is rated down to your baby's weight. Whichever you pick, it must be installed rear-facing and meet your country's safety standard.

Is it safe to buy a used infant car seat?

It is usually not worth the risk. The NHS advises against buying a secondhand car seat because it may have been damaged in a crash you cannot see, and it may be missing parts or instructions. If a seat is handed down from someone you trust, only use it if you know its full history, it has never been in a crash, it is not expired, and you have the manual. When in doubt, buy new.

How tight should an infant car seat be installed?

Once installed at the belt path, the seat should not move more than about an inch side to side or front to back when you pull firmly at the base. The harness on your baby should also be snug: the AAP says you should not be able to pinch any slack at the shoulder straps, and the chest clip sits at armpit level. If you are unsure, a certified child passenger safety technician can check it for free at many fire stations and clinics.

When can my baby stop using the infant car seat?

Switch only when your baby reaches the highest weight or height the seat allows, listed on the seat and in its manual. At that point move to a convertible seat and keep your child rear-facing as long as possible. The AAP recommends staying rear-facing until your child reaches the top weight or height limit of that seat, which is often age two or older. Do not rush to turn the seat forward-facing based on age alone.

Do car seats really expire, and how do I check?

Yes. Plastic and foam degrade over years of heat and cold, and safety standards change, so manufacturers print an expiration or useful-life date on the seat. Look for it molded into the plastic on the bottom or back of the shell, or on a sticker, and check the manual or manufacturer's website if you cannot find it. Stop using a seat past that date, and never use one with an unknown history.

Infant Car Seats: How to Choose, Install, and Know It Is Safe

Creator: The newborn.mom team
Published: 2026-05-29

A plain, sourced guide to choosing an infant car seat, installing it tightly, and checking the harness so your baby rides safely from the first trip home.

By The newborn.mom teamUpdated May 29, 20266 min read

Your baby's first car seat is the one piece of gear that has to work before you even leave the hospital. The good news is that choosing one is simpler than the wall of boxes at the store makes it feel. This guide walks you through the type to buy, how to put it in tightly, and how to check that your baby is actually safe in it.

Start with the right type of seat

Newborns ride rear-facing, period. The AAP recommends that all infants ride rear-facing starting with their first ride home from the hospital, because a rear-facing seat better protects a baby's head, neck, and spine in a crash (HealthyChildren.org / AAP). That narrows your real choice to two seat types.

Rear-facing-only infant seats

These are the small seats with a carry handle and a base that stays buckled in the car. You click the carrier in and out, which is handy for a sleeping baby. They have lower weight and height limits, so most babies outgrow them in their first year or so. They also tend to pair with strollers as a travel system.

Convertible seats used rear-facing

A convertible seat is bigger, stays in the car, and starts rear-facing before later turning forward-facing. It can last longer, but check that its lowest rear-facing weight rating fits a newborn, and that it physically fits your car. There is no carry handle, so you lift the baby in and out each trip.

Match the seat to your car and your baby

A seat is only as good as its fit. The NHS suggests trying a few seats in your own car before you buy, ideally with help from a retailer trained in fitting them (NHS).

Three things to confirm before you pay:

It fits your vehicle. Rear-facing seats take up front-to-back space. A tall seat can crowd the front passenger. Test-fit it in the actual back seat of your actual car.
It fits a newborn. Check the minimum weight on the label. Small or premature babies may need a seat rated low, and your hospital can advise.
It uses a system your car supports. Many cars have lower-anchor or ISOFIX connectors built in to make fitting simpler. If yours does not, a seat can still install correctly with the vehicle seat belt.

One thing that should not drive your decision is price. A more expensive seat is not a safer seat: every seat sold has to meet the same federal safety standard, so buy the one that fits your car, your baby, and your budget.

Avoid a used seat with an unknown history

A hand-me-down seat is tempting, but it carries real risk. The NHS advises not to buy a secondhand car seat, because it could have been damaged in an accident you cannot see and may be missing parts or instructions (NHS).

If a friend or relative offers a seat, only use it when you know its full history, it has never been in a crash, it is not expired, and you have the manual. Otherwise, a new seat is the safer call. The AAP also says not to use a seat that has been in a moderate or severe crash (HealthyChildren.org / AAP).

Install it so it does not move

Most installation mistakes come down to a loose base or a loose harness. Work through the seat's own manual and your car's manual together. They are written for exactly this.

Lock the base down tight

Install rear-facing in the back seat, at the recline angle marked on the seat. Then use either the lower anchors or the vehicle seat belt at the belt path, not both at once unless the manufacturer allows it. When you grab the seat at the belt path and pull firmly, it should not shift more than about an inch in any direction. If it slides, you need more force on the belt or anchor strap.

Get the harness right

Settle your baby with their back flat against the seat, straps coming from at or below the shoulders for rear-facing. The AAP says the harness should be snug enough that you cannot pinch any slack at the shoulder straps, and the chest clip should sit at the center of the chest, even with your baby's armpits (HealthyChildren.org / AAP). Skip bulky coats under the harness, since they compress in a crash and leave the straps loose.

If any of this feels uncertain at 3am the night before discharge, you are not alone. A certified child passenger safety technician can check your install for free at many fire stations, hospitals, and clinics. The AAP notes that everyone can benefit from professional help to confirm the seat is installed correctly.

Register the seat and keep using it correctly

Fill out and mail the registration card, or register on the manufacturer's website, so you get notified if the seat is recalled (HealthyChildren.org / AAP).

Then keep two habits. First, keep your baby rear-facing as long as possible; the CDC's plain advice is to keep children rear-facing as long as possible and properly buckled in the back seat (CDC). Move to the next stage only when your baby hits the top weight or height the seat allows. Second, buckle up every single trip, even short ones. Among children killed in crashes, 43% were not buckled up (CDC).

When to ask for help from your provider

Reach out for hands-on guidance, not just a web search, if any of these apply:

Your baby was born early or small, slumps forward, or seems to struggle to breathe in the seat. Ask your pediatrician about a positioning check before discharge.
You cannot get the seat to install tightly, or the straps never feel right.
The seat was in a crash, is past its expiration date, or you do not know its history.

Your hospital, pediatrician, and a certified child passenger safety technician can all help in person. This article is general information, not medical advice. For your own baby and your own car, follow the seat and vehicle manuals and check with your own clinician.

Frequently asked questions

What kind of car seat does a newborn need?: A newborn needs a rear-facing seat used in the back seat. Most parents start with a rear-facing-only infant seat, which has a carry handle and a base that stays clicked in the car. A convertible seat that starts rear-facing also works as long as it is rated down to your baby's weight. Whichever you pick, it must be installed rear-facing and meet your country's safety standard.
Is it safe to buy a used infant car seat?: It is usually not worth the risk. The NHS advises against buying a secondhand car seat because it may have been damaged in a crash you cannot see, and it may be missing parts or instructions. If a seat is handed down from someone you trust, only use it if you know its full history, it has never been in a crash, it is not expired, and you have the manual. When in doubt, buy new.
How tight should an infant car seat be installed?: Once installed at the belt path, the seat should not move more than about an inch side to side or front to back when you pull firmly at the base. The harness on your baby should also be snug: the AAP says you should not be able to pinch any slack at the shoulder straps, and the chest clip sits at armpit level. If you are unsure, a certified child passenger safety technician can check it for free at many fire stations and clinics.
When can my baby stop using the infant car seat?: Switch only when your baby reaches the highest weight or height the seat allows, listed on the seat and in its manual. At that point move to a convertible seat and keep your child rear-facing as long as possible. The AAP recommends staying rear-facing until your child reaches the top weight or height limit of that seat, which is often age two or older. Do not rush to turn the seat forward-facing based on age alone.
Do car seats really expire, and how do I check?: Yes. Plastic and foam degrade over years of heat and cold, and safety standards change, so manufacturers print an expiration or useful-life date on the seat. Look for it molded into the plastic on the bottom or back of the shell, or on a sticker, and check the manual or manufacturer's website if you cannot find it. Stop using a seat past that date, and never use one with an unknown history.