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When to Move from Infant Car Seat to Convertible

The answer to the question from the title goes well beyond blurbing out a number.

If you’re anything like me and want to understand the logic and the reasons behind the parenting decisions you make.

baby in a car seat

That’s especially true in the wake of the Consumer Report issuing new guidelines about switching to a rear-facing car seat.

In this guide, I’ll be precise about all the questions you might have and go broad at times and answer questions you probably didn’t know you should be asking.

Let’s get to it.

The question of ‘when’

While it can be tempting to switch from an infant car seat to a convertible, you’ll need to understand the logic behind the transition to make it as seamless and as safe as possible.

The biggest question in the ‘infant car seat vs. convertible car seat’ dilemma is this, “When to switch from infant car seat to convertible?”

Consumer Reports testing

Rear-facing seats are the commonly accepted standard for any child below the age of two.

Consumer Reports testing has provided proof that keeping your child rear-facing is the way to go. They have also determined that the safest time to switch from an infant car seat to a convertible car seat is when the baby is one year old.

baby laying in a car seat

In their experiments, researchers tested a rear-facing convertible car seat and a rear-facing infant car seat using a 22-pound dummy. Below are the results.

The results

In 50% of the infant seats, the tests found that the dummy’s head would hit the back of the front seat. With convertible seats, that risk is substantially lower – it happened only once per 25 tests.

Here’s why

Once the distance from the child’s head to the top of the outer shell of the infant seat is less than an inch from, there is an increased risk of them hitting their head when a crash happens.

A child typically gets too close to the ‘one-inch mark’ at about one year of age.

This means that you need to switch from the infant car seat to a convertible by the time they are a year old, even if they have not exceeded the infant carrier’s weight and height limits.

Let’s take a step back and look at the differences between the two types of car seats.

​Infant Car Seat

While there are many convertible car seats available for your child from birth to toddler, and even until they start using vehicle seat belts, most parents will go for the cheaper infant car seat.

infant car seat

It’s a bucket-style seat designed to be used for the first year or two. It’s rear-facing only – this one’s a biggie, and I’ll be getting back to the importance of forward-facing and rear-facing modes throughout this guide.

The infant car seat has a few major things going for it:

  • It’s made for the smallest of babies – and can only be used in the recommended rear-facing mode (duh). This carries a certain peace of mind when traveling with your baby in the car.
  • Convenience – makes all the difference when you need to get the sleeping child out of their seat without waking them up
  • Flexible use – unlike your convertible car seat, a good infant car seat can be unhooked easily from its base and installed on a stroller or carried into the house, which is quite convenient

Related read: Best infant car seats

The mystery of the newborn insert

Time and again, I keep getting questions about the proper use of a newborn insert in an infant seat.

infant car seat
Credit: Consumer Reports

I don’t blame the parents because many of the manuals I’ve seen over the years are either vague about it or list a few criteria that clash.

The two rules of thumb I’ll list below DO NOT overrule the manual. They’re meant to help you interpret the information in the manual.

  1. Use a newborn from birth until the child is 11-15 lbs
  2. It’s safe to use it only when the baby’s shoulder reach the straps without the insert

If you’re a two-car family

Most modern infant seats snap off and on to a fixed base, and you can often get the two separately.

This means that you’ll probably need one seat and two bases.

​Convertible car seat

​Just like the infant car seat, the toddler car seat also has its advantages.

Side view of a happy little boy looking at camera while his mother buckling him in a car seat
  • You can use a convertible seat from birth right through to toddlerhood until the age of 12, when they shift to using car safety belts (or until they reach the weight limit, of course)
  • One convertible seat is likely to have you covered for years – if you bought a convertible that can be used in rear-facing forward-facing for children from the age of 2 and as harnessed booster seats from 8 years

Related reads:

My top 3-in-1 car seat picks

Best baby seats for small cars

When to switch to a convertible car seat

When the Child Maxes Out the Weight Limit

The good thing about car seats is that all of them will typically come with weight and height limits. It’s essential to read the car seat owner’s manual and have a thorough understanding of it before you put it to use.

It would be best to be ready with a convertible car seat when the child maxes out the weight of their car seats, typically between 25 and 35 pounds, depending on the brand.

​Similar to weight limits, a car seat also has height limits that you’ll need to adhere to. You need to read your car seat owner’s manual and follow it religiously to ensure your child is safe.

Head too close to the top of the seat

Sometimes, you’ll need to move on from a car seat even before they reach the weight or height limit. These are the cases of babies with particular body types that don’t fit the charts – it rarely happens, but you need to know it.

Here’s a rule of thumb – if the top of their head gets too close to the top of the seat, you should move on. The cut-off for “too close” is one inch.

That goes, whether they have or haven’t reached the weight limit.

Consider booster at age 4

When the time comes (typically at about the age of 4), you can consider moving on from a convertible to a booster seat, which allows you to use the car safety belt and lift them higher.

Most of them love it.

Switching from rear-facing to forward-facing position

If you already looked into this and you’re stumped, don’t feel bad.

Even the experts in the field can’t wholly agree on the exact age to make the switch.


The stir-up that we see right now is a direct consequence of one of the main studies supporting the rear-facing recommendations being retracted in 2017. (you can read more about that here).

Does that mean rear-facing is not safer?

It does not.

While it may be true that saying it’s five times safe is overblown, pretty much all experts still agree that rear-facing is the way to go.

Infant Car Seat vs. Convertible Car Seat

Are you stumped on whether to go for the infant car seat or the convertible seat?

Well, you are not alone; I still remember the first time we were expecting.

While some parents swear by the infant car seat and others by the convertible car seat, your choice will typically come down to what you’re looking for. However, even the convertible or the infant car seat has its advantages and disadvantages.

infant car seat

The most important thing to consider is the needs of the newborn infant, which are typically very different from that of the toddler or older child.

The following are some of the most important things to take into consideration when making a choice:

  • Fit to child – Most infant car seats will fit infants weighing in from as little as 5 pounds up to about 30 pounds. For most convertible car seats, you have to use an infant insert to fit the newborn.
  • Incline angle – It is generally recommended that you incline your infant at a 45-degree angle. Most infant car seats will allow for this angle, making the ride comfortable for the child. Some convertible car seats, such as the Britax USA Advocate, the Cybex Sirona M, or Chicco Nextfit 2018, have angle recliners to achieve the recommended angle. However, most convertibles will need blankets to get the angle right. It’s also fair to say that they’re not as comfortable.
  • Harness tightness – For your infant, it is essential to have harnesses with the proper tightness – you want a 5-point harness that’s tight enough to pass the pinch test. Most convertible car seat harnesses are too long to fit the tiny infant, making them unsafe.
the pinch test
  • Strap positioning – just as important as the harness tightness. You need a car seat with straps positioned at or just below the child’s shoulders. Given the newborn infant usually has a torso about 7 inches, you need a car seat whose lower strap slots can fit that torso length.

You can read more on infant vs convertible car seats here.

Related reads: Chicco Keyfit vs Fit 2

Pros of Infant Car Seats

  • Infant car seats come with a base, and hence they can be quickly snapped in and out of the car, making it possible to lug the car seat with the infant in it.
  • They offer the perfect fit for even the smallest of babies up to a minimum of five pounds.
  • You can attach it to a stroller and jog or walk around with the child.
  • You can lug it around without waking up the child – this makes traveling much easier.

Cons of Infant Car Seats

  • Given that it typically has lower height and weight limits, you will typically require a convertible or all in one car seat before the child turns two years which adds to costs

Pros of Convertible Car Seats

  • Reduces costs, especially if you are on a budget as you only need to buy one car seat that your child will use for several years
  • Most convertible car seats are suitable for children from 5 pounds and above and turn from rear-facing to forward-facing to accommodate the needs of the growing child

Cons of Convertible Car Seats

  • They do not come with a base – installing or uninstalling them from the car can be quite an inconvenience.
  • Some of the large convertible seats do not provide a good fit or angle for the newborn child, making them relatively unsafe and uncomfortable
  • They are cumbersome, making it almost impossible to lug them around as you would an infant car seat
  • They cannot be attached to a stroller for use when jogging walking or doing other tasks
  • With no base, installing will usually awaken the sleeping child

My Take on What Car Seat You Should Buy

Even as consumer reports recommend that you switch to a convertible car seat sooner rather than later, you can still enjoy the benefits of the infant car seat while still keeping your child safe.

best forward facing car seat

Even if you have to spend more money when shifting to a convertible car seat later, the convenience of an infant car seat is worth the money.

So when to switch to a convertible car seat

If we’re going by the book, this would be the way to go – buy an infant car seat and get the convertible later, when the child exceeds their infant car seat’s weight and height limits.

The decision is not simple, but you now have all the necessary know-how to make it.

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