Infant Car Seat Size Explained in Detail by age, weight & height

An infant car seat is a rear-facing car seat with a bucket-style shape that most parents utilize for up to age 2 of their baby’s life. After that, some parents prefer using convertible car seats. Either way, the National Highway Traffic Safety Administration demands you get a rear-facing car seat for your infant. But what about infant car seat size? All is explained by age, weight, and height.

Grabbing an oversize or undersized child rear car seat for your baby means they will strain to stretch or have excess space around them. This can be dangerous as your child has minimum safety without a perfect fit. You can consult a Child Passenger Safety Technician skilled in creating exclusive car seats for all infant sizes to avoid this. 

Example of infant car seat size and baby car seat dimensions that matter (brand: Foonf )
Example of infant car seat size and baby car seat dimensions that matter (brand: Foonf )

Do you want to learn how to find the right infant car seat size for your child? Read on!

Jump right into the Frequently Asked Questions

Related: Pampers Size Chart for all ages by type (size charts included), Huggies Size Chart for all ages by type (size charts included), Shoe size for Babies and Toddlers

Table of content on baby car seat sizing

Infant Car Seat Size Chart

Related: Britax car seat size chart by model, weight and age

infant car seat size
Image Source: Michael Hession

Infant Car Seat Size Limit Chart: BOYS

Car Seat TypeAge (Month)WeightHeight
Rear-Facing Car Seat621 lbs 9.5 kgs28.5 inch 72.4 cm
Rear-Facing Car Seat924.5 lbs 11.1 kgs30 inch 76.2 cm
Rear-Facing Car Seat1227.5 lbs 12.5 kgs32 inch 81.3 cm
Rear-Facing Car Seat1529.5 lbs 13,4 kgs33 inch 83.8 cm
Rear-Facing Car Seat1831 lbs 14.1 kgs34.5 inch 87.6 cm
Rear-Facing Car Seat2132 lbs 14.5 kgs35.5 inch 90.2 cm
Rear-Facing Car Seat2433 lbs 14.9 kgs36.5 inch 92.7 cm
Rear-Facing Car Seat2733.5 lbs 15.2 kgs37.5 inch 92.3 cm
Rear-Facing Car Seat3034.5 lbs 15.6 kgs38.5 inch 97.8 cm
Rear-Facing Car Seat3335.5 lbs 16.1 kgs39.5 inch 100.3 cm
Rear-facing/ Forward-facing car seat3637 lbs 16.8 kgs40.5 inch 102.9 cm
Rear-facing/ Forward-facing car seat4838.5 lbs 17.5 kgs43.5 inch 110.5 cm

Infant Car Seat Size Limit Chart: GIRLS

Car Seat TypeAge (Month)WeightHeight
Rear-Facing Car Seat619 lbs 8.6 kgs27.5 inch 69.8 cm
Rear-Facing Car Seat922.5 lbs 10.2 kgs29.5 inch 74.9 cm
Rear-Facing Car Seat1225 lbs 11.3 kgs31 inch 78.7 cm
Rear-Facing Car Seat1527.5 lbs 12.5 kgs32.5 inch 82.6 cm
Rear-Facing Car Seat1829 lbs 13.2 kgs33.5 inch 85.1 cm
Rear-Facing Car Seat2130.5 lbs 13.8 kgs35 inch 88.9 cm
Rear-Facing Car Seat2432 lbs 14.5 kgs36 inch 91.4 cm
Rear-Facing Car Seat2733.5 lbs 15.2 kgs37 inch 93.9 cm
Rear-Facing Car Seat3035 lbs 15.9 kgs38 inch 96.5 cm
Rear-Facing Car Seat3336.5 lbs 16.6 kgs39 inch 99.1 cm
Rear-facing/ Forward-facing car seat3638 lbs 17.2 kgs40 inch 101.6 cm
Rear-facing/ Forward-facing car seat4844 lbs 19.9 kgs42.5 inch 107.9 cm

Infant Car Seat Size Comparison Chart

Safe Car Seat NameRF Weight LimitRF Height LimitBottom Harness Slot2nd Harness Slot Closest Buckle SlotInside Hip Width 
Baby Trend EZ Flex-Loc 325 – 32 lbs 2.3 – 14.5 kgs  32 inch or less  81.3 cm or less8 inch 20.3 cm 12 inch  30.5 cm5 inch 12.7 cm10 inch  25.4 cm
Baby Trend Flex-Loc 305 – 30 lbs 2.3 -13.6 kgs30 inch  76.2 cm7.5 inch 19.1 cm11.5 inch  29.2 cm5 inch  12.7 cm10 inch  25.4 cm
B-Safe4 -30 lbs 1.8 – 13.6 kgs  32 in. or less 81.3 cm or less5.5 in. 13.9 cm  11.5 in. 29.2 cm
4 inch 10.2 cm9 inch 22.9 cm
Britax B-Safe 354-35 lbs. 1.8 – 15.9 kgs32 in. or less 81.3 cm or less5 inch  12.7 cm7 inch 17.8 cm4 inch 10.2 cm8 inch  20.3 cm 
B-Safe 35 Elite4 – 35 lbs. 1.8 – 15.9 kgs
32 in. or less 81.3 cm or less
5.5. or 6.5 in. 13.9 – 16.5 cm 11.5 in. 29.2 cm
4 in. 10.2 cm
8 in. 20.3 cm 
Britax Endeavours4 – 35 lbs. 1.8 – 15.9 kgs
32 in. or less 81.3 cm or less5.5. or 6.5 in. 13.9 – 16.5 cm11.5 in. 29.2 cm4 in. 10.2 cm8 in.  20.3 cm 
Chicco Keyfit 224 – 22 lbs. 1.8 – 9.9 kgs30 in. or less 76.2 cm or less6.5 or 8 in. 16.5 or 20.3 cm 10 in.  25.4 cm6 in. 15.2 cm9.75 in.  24.8 cm
Chicco KeyFit 30 infant car seat size4 – 30 lbs. 1.8 – 13.6 kgs30 in. or less 76.2 cm or less
6.5 or 8 in. 16.5 or 20.3 cm 10 in. 25.4 cm6 in. 15.2 cm9.75 in.  24.8 cm
Combi Shuttle 35Birth-35 lbs. Birth – 15.9 kgs33  in. or less 83.8 cm or less8.5 in. 21.6 cm14.5 in. 36.8 cm5.25 in. 13.3 cm8 in. 20.3 cm 
 
Cosco Light n Comfy DX4 – 22 lbs. 1.8 – 9.9 kgs29  in. or less 73.7 cm or less5.5 in. 13.9 cm7.5 in. 19.1 cm3.5 in. 8.9 cm    –
Cosco Light n Comfy LX4 – 22 lbs. 1.8 – 9.9 kgs29  in. or less 73.7 cm or less5.5 in. 13.9 cm7.5 in. 19.1 cm
3.5 in. 8.9 cm    –
Cybex Aton4 – 32 lbs. 1.8 – 14.5 kgsUp to 30 in. Up to 76.2 cm7.5 or 8 in. 19.1 or 20.3 cm 10 in.  25.4 cm6 in. 15.2 cm9.5 in. 24.1 cm
Cybex Aton 2
4 – 32 lbs. 1.8 – 14.5 kgsUp to 30 in. Up to 76.2 cm
7.5 or 8 in. 19.1 or 20.3 cm 10 in. 25.4 cm  6 in. 15.2 cm9.5 in. 24.1 cm
Cybex Aton Q  4 – 35 lbs. 1.8 – 15.9 kgs
30 in. (1″ above head)  76.2 cm (2.5 cm above head)7.5 in. 19.1 cm12.5 in. 31.8 cm    –9.5 in. 24.1 cm
Disney Baby Mickey / Minnie Light n Comfy Luxe4 – 22 lbs. 1.8 – 9.9 kgs29 in. or less 73.7 cm or less5.5 in. 13.9 cm7.5 in. 19.1 cm
3.5 in. 8.9 cm    –
Evenflo Embrace 354 – 35 lbs. 1.8 – 15.9 kgs
Up to 30 in. Up to 76.2 cm6 in. 15.2 cm8.5 in. 21.6 cm4 in. 10.2 cm
9.5 in. 24.1 cm
Evenflo Nurture5 – 22 lbs. 2.3 – 9.9 kgs19-29 in. 48.3 – 73.7 cm5.5 in. 13.9 cm7.5 in. 19.1 cm
4 in. 10.2 cm    –
GB Asana 35 DLX4 – 35 lbs. 1.8 – 15.9 kgs
32 in. or less 81.3 cm or less6 in. 15.2 cm11 in. 27.9 cm4 in. 10.2 cm9 in. 22.9 cm
GB Asana 35 LTE4-35 lbs. 1.8 – 15.9 kgs32 in. or less 81.3 cm or less6 in. 15.2 cm11 in. 27.9 cm4 in. 10.2 cm
9 in. 22.9 cm
Graco SnugRide Classic Connect 225-22 lbs. 2.3 – 9.9 kgs
29 in. or less 73.7 cm or less7.5 in. 19.1 cm
10.25 in. 26.0 cm5 in. 12.7 cm
10.25 in. 26.0 cm
Graco SnugRide Classic Connect 304-30 lbs. 1.8 – 13.6 kgs
30 in. or less 81.3 cm or less7 in. 17.8 cm8.5 in. 21.6 cm2.5 in. 6.4 cm9 in. 22.9 cm
SnugRide Classic Connect 355-35 lbs.Up to 32 in. Up to 81.3 cm7 in. 17.8 cm9.5 in. 24.1 cm  5.5 in. 13.9 cm  10 in.  25.4 cm
Hauck PROsafe354-35 lbs. 1.8 – 15.9 kgs
32 in. or less 81.3 cm or less5.5 in. 13.9 cm7 in. 17.8 cm  4 in. 10.2 cm
9 in. 22.9 cm
iCoo iGuard354-35 lbs. 1.8 – 15.9 kgs
  32 in. or less 81.3 cm or less5.5 in. 13.9 cm7 in. 17.8 cm4 in. 10.2 cm
9 in. 22.9 cm  
Ingenuity InTrust 35 Pro4-35 lbs. 1.8 – 15.9 kgs32 in. or less  81.3 cm or less5.5 in. or 6.5 in. 13.9 – 16.5 cm 11 in. 27.9 cm6 in. 15.2 cm      –
Maxi-Cosi (Dorel) Mico AP5-22 lbs. 2.3 – 9.9 kgs19-29 in. 48.3 – 73.7 cm7.5 in. 19.1 cm10.75 in.  27.3 cm3 in. 7.6 cm11.5 in. 29.2 cm
Maxi-Cosi (Dorel) Mico Max4-30 lbs. 1.8 – 13.6 kgs
19-32 in. 48.3 – 81.3 cm7.5 in. 19.1 cm
8.75 in. 22.2 cm4 in. 10.2 cm10.5 in. 26.7 cm
Mia Moda Certo / Viva Supreme4 – 22 lbs. 1.8 – 9.9 kgs
Less than 29 in. Less than 73.7 cm6.75 in. 17.1 cm12 in. 30.5 cm4 in. 10.2 cm    –
Mountain Buggy protect4 – 35 lbs. 1.8 – 15.9 kgs
32 in.  81.3 cm 6 in. 15.2 cm11.25 in. 28.6 cm4 in. 10.2 cm      –
Nuna Pipa4-32 lbs. 1.8 – 14.5 kgs32 in. or less 81.3 cm or less6 or 7 in. 15.2 – 17.8 cm9 in. 22.9 cm5 in. 12.7 cm    –
Orbit Baby Infant Seat G34-30 lbs. 1.8 – 13.6 kgs
19-32 in. 48.3 – 81.3 cm8 in. 20.3 cm 
10 in. 25.4 cm
 
6 in. 15.2 cm8 in. 20.3 cm 
Peg Perego Primo Viaggio 4-354-35 lbs. 1.8 – 15.9 kgs
32 in. or less 81.3 cm or less5 in. 12.7 cm11.5 in. 29.2 cm
6.5 in. 16.5 cm      –
Safety 1st (Dorel) onBoard 35 4-35 lbs. 1.8 – 15.9 kgs
32 in. or less 81.3 cm or less5.5 in. 13.9 cm11.5 in. 29.2 cm
 
3 in. 7.6 cm  10.5 in. 26.7 cm
Safety 1st Light n Comfy4-22 lbs. 1.8 – 9.9 kgs29 in. or less 73.7 cm or less5.5 in. 13.9 cm7.5 in. 19.1 cm3.5 in.  8.9 cm    –
Team Tex America Baby RideUp to 22 lbs. Up to 9.9 kgs29 in. or less 73.7 cm or less8.5 in. 21.6 cm11.5 in. 29.2 cm
 
4.5-5 in. 11.4-12.7 cm  9 in. 22.9 cm  
UPPAbaby Mesa4-35 lbs. 1.8 – 15.9 kgs
32 in. or less 81.3 cm or less5.5 in. 13.9 cm10 in. 25.4 cm
    –    – 
Urbini Petal4-35 lbs. 1.8 – 15.9 kgs
Up to 32 in. Up to 81.3 cm6 in. 15.2 cm11.5 in. 29.2 cm
4.5 in. 11.4 cm10 in. 25.4 cm
~Baby Trend Flex-Loc 22 (discontinued)5-22 lbs. 2.3 – 9.9 kgs
28.5 in. or less 72.4 cm or less8 in. 20.3 cm 11.5 in. 29.2 cm
5 in. 12.7 cm
9.5 in. 24.1 cm
~Combi Shuttle 22 (discontinued)5-22 lbs. 2.3 – 9.9 cm29 in. or less 73.7 cm or less
8 in. 20.3 cm11 in. 27.9 cm
5 in. 12.7 cm11 in. 27.9 cm

How To Choose the Right Infant Car Seat Size

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The right baby infant car seat size should allow space for your child to stretch. According to the Federal Safety Standards, the seat should also provide maximum comfort and safety for the baby. 

It should be compatible with your vehicle seat to ensure stability and impact protection if there’s an accident or a swift stop. When checking the measurements, consider different parts of your infant’s body. For instance, the upper thighs, height, and weight. Then compare them to the minimum weight, maximum weight, minimum height, and infant insert availability. 

Infant car seat size accessories are also essential when buying a rear-facing infant car seat. Some may alter the dimensions, for instance, the infant inserts can adjust the inside hip width when fitted. In addition, accessories such as harness straps, an anti-rebound bar, a five-point harness, and a shoulder belt provide extra protection for your child. 

Depending on your child’s age, you can purchase a rear-facing car or convertible seat. Typically,  a CPS technician will advise you to buy rear-facing seats for kids age 2 and below. Kids who are two years and above can use forward-facing seats comfortably. 

Suppose you’re working on a tight budget; you can compare the price range of infant car seats size amazon or get second-hand car seats. Nevertheless, getting combination seats such as a  rear-facing convertible seat would offer your toddler better protection and luxury if you can afford expensive seats like Evenflo Gold Revolve360.

Learn more about how to choose the right car seat for your infant (video)

General Car Seat Guide | Which Car Seat Do I Use Next? by The Baby Cubby

Frequently Asked Questions

What size car seat comes after an infant?

The type of seat that comes after the infant period is the convertible and booster car seats. The forward-facing limits for kids older than infants are usually 40.5 inches and 16.8 kgs minimum. Hence, you should check the forward-facing convertible car seat features before grabbing one for your kid.

Do I Need An Infant Car Seat? Are Convertible Car Seats Better? by Kevin Lu

What is the biggest infant car seat?

One of the largest infant car seats is Doona Infant Car Seat which comes with a LATCH anchor, head support, infant insert, vehicle seat protector, and a Doona Infant Car Seat Stroller. 

What is the smallest infant car seat?

The smallest infant car seat is the Clek Foonf which measures 16.9 inches wide. Suppose you have a small vehicle; this would be a great purchase.

Can an Infant car seat be used as a part of the stroller?

Yes, some infant car seats can be used as part of strollers, such as Doona and Meta. All you need to do is confirm the infant car seat size and stroller measurements match for perfect fitting. 

What are the biggest infant car seat manufacturers? 

The biggest infant car seat manufacturers include Britax, Chicco, Graco, Maxi Cosi, Peg Perego, and Safety First. These companies offer the best infant and toddler car seats. 

Conclusion 

Every vehicle owner deserves the safest car seat for their infants, which can be challenging to find. But thanks to the Federal Motor Vehicle Safety Standard 213, it provides you with all the essential information. For instance, the correct angle, installation process, and crotch strap for your kid’s age.

With an infant-only seat size chart, you can secure the right infant car seat size for your toddler to provide maximum protection. Having any car seat concerns? Drop your question in the comments below, and we will have a professional help you sort it out!

Picture in this post is by Alexander Grey on Unsplash

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