When is my baby too big for an Infant car seat?

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Written by: Fatima O. Millers, CPST

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Unless you are getting an All-In-One car seat, you will probably use three different car seats for your child: an infant seat, a convertible seat, and a booster seat.

If your child is in an infant car seat, how can you determine whether he/she is too big for it and needs to switch to a convertible car seat?

Well that’s why we exist, here is a checklist to follow to make sure that your little one has outgrown their current infant seat and is ready for the next one.

When to switch from an Infant seat to a convertible seat?

Your child has outgrown their infant seat and they ready for a convertible seat when either of the following conditions is met:

The child has reached the maximum weight limit of the infant car seat which ranges between 30 to 35 pounds, though some car seats have a weight limit of only 22 lbs.

The child has maxed out the height limit of the infant car seat, which is typically 30 to 32 inches. Some infant car seat has a height limit as low as 29 inches and there are a couple of other car seats out there that can last all the way to 35 inches tall. 

The top of your child’s head is less than an inch from the top of the seat when buckled in. Some infant car seats require slightly more clearance than one inch, while a few seats allow the child’s head to reach the top of the car seat shell as they grow.

When is my baby too big for an Infant car seat

So depending on your baby’s size, a switch to a convertible car seat can be possible anywhere between 9 to 24 months. 

Bigger than average kids will likely be ready to ditch their infant seat and make the transition to a convertible car seat earlier, possibly closer to the 9-month mark. 

On the other hand, smaller or average-sized children may continue using their infant seat until closer to 24 months.

When can you move your infant to a convertible seat?

There is one additional factor that might prompt you to transition your baby from an infant carrier to a rear-facing convertible car seat earlier.

As your baby grows, he/she will naturally gain weight, and when combined with the weight of the carrier, it can make toting your baby around in the infant car seat more difficult.

When to switch my baby from an Infant car seat

This put a strain on your arms, back, and overall posture, especially when walking longer distances.

Infant carriers (without the base) can weigh up to 11 pounds and by adding your child’s weight you are looking at 40 pounds or more of weight to carry around. 

Parents that can’t handle this weight, they can choose to switch to a rear-facing convertible car seat before their baby maxes out the weight and height limits. It’s absolutely safe.

Infant car seats are all about portability but convertibles aren’t meant to be carried around or taken out of the car once you install them. 

Once you install a convertible car seat properly in your car, it’s supposed to stay there. You can’t just pop it out and carry it around like you would with an infant carrier. 

Good to know: Convertible car seats are designed to be used in both rear-facing and forward-facing. And a rear-facing convertible car seat that fits your baby’s height and weight limits well is considered to be just as safe as an infant car seat.

Before you go ahead and make the switch to the next car seat stage, consult your car seat’s manual and check your baby’s stats (height and weight).

If you have any doubts about transitioning from an infant seat, it’s best to reach out to a certified car seat technician for advice.


Can babies be in the car seat for too long?

Babies should not spend too much time in a car seat. Babies, especially newborns, and infants, have developing bodies, and spending excessive time in a car seat can cause strain on their delicate spine and muscles. It can also restrict their movement and natural development. For longer journeys, plan regular breaks every two hours or so (Read about the 2-hour rule), and give them an opportunity to move, stretch, and play.

What is the maximum weight for an infant car seat?

The maximum weight for an infant car seat can vary depending on the specific car seat model and brand. But, a common weight limit for infant car seats is typically around 30 to 35 pounds (13.6 to 15.9 kilograms).

What is the maximum height for an infant car seat?

Infant car seats are designed to accommodate babies up to a certain height. The height limit for an infant car seat is often around 28 to 32 inches (71 to 81 centimeters). It’s important to note that these measurements can vary between different car seat models and brands.

Please note: The content provided on Car Seat Parent, including all materials and information, is not intended to serve as medical or health advice. Always consult with ahealthcare professional regarding your specific circumstances, especially when it concerns the safety and well-being of your child in relation to car seat use.

About Fatima O. Millers, CPST

Founder and Editor-in-Chief, Fatima delivers insightful car seat reviews and recommendations. Combining her CPST expertise with an engineering background, her advice is both safe and practical.

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