Do you have to buy two car seats?

Quick Answer

Most parents will need to buy two car seats – one for each child. While kids can share a seat, it’s not recommended. Each child should have their own car seat for safety and comfort. Buying two seats ensures you always have a seat for each child when traveling together. Some exceptions may apply based on ages and local laws.

Do you need a car seat for each child?

The general recommendation is yes, each child should have their own car seat when riding in a vehicle. Here are some key reasons why:


Car seats are designed to protect children in the event of a crash or sudden stop. They spread crash forces across the strong parts of a child’s body. Car seats have been proven to significantly reduce injury and death in children.

To work properly, car seats must be used correctly on every ride. This includes being properly secured, positioned at the right angles, fitted to the child’s size, and not expired. It’s extremely difficult to ensure proper use for two kids sharing one seat.


Children come in all different shapes and sizes. A car seat that fits one child well likely won’t fit another child the same way. An ill-fitting seat can be uncomfortable or unsafe. Kids squished together in one seat may distract and pinch each other. Each child will be most comfortable in a seat designed for their own body.


Life is easier when each child has their own seat. You don’t have to shuffle seats between cars or kids. Both children can be buckled in quickly at the same time. You always have a seat handy for each child, even if driving separately.


Many states have laws requiring each child to be properly secured in their own car seat or booster seat. Children must remain in car seats until at least age 2-7, depending on location. Violating these laws can result in fines or charges. Having two seats ensures you are complying with safety laws.

When can siblings share a car seat?

While separate seats are ideal, there are some exceptions where children may temporarily share a seat:

Taxi or rideshare

If taking a taxi or rideshare, two small children under age 4 may be able to share a seat if absolutely necessary. This should only be done for short, occasional trips. Never place two older/larger kids or forward-facing and rear-facing kids together.

Child care carpools

Many daycares employ specialized vans with integrated rows of forward-facing seats and five-point harnesses. Multiple older children may safely share these seats for commuting to school or activities. They provide an alternative to hauling lots of individual car seats.

Older siblings

In a pinch, an older child (over age 5) could hold a baby on their lap and share the adult seatbelt. This should only be done as an exception for brief trips. The adult’s lap is not as safe as a proper car seat used alone.

Financial hardship

For families unable to afford two seats, it may be possible to borrow, rent, or purchase discounted seats from nonprofit organizations and government programs. This ensures each child still has a proper seat of their own.

What types of car seats do you need?

To cover children at different ages and sizes, most families need at least two different types of car seats:

Infant seat

An infant/rear-facing only seat is required for all babies under 1 year old and under 20-22 lbs. These have a handle for carrying and lie reclined to support infants. They always face the rear of the car and often come as part of a stroller system.

Convertible seat

A rear-facing convertible seat is needed once baby outgrows their infant seat. These seats can be used rear-facing up to age 2-4 and 40+ lbs, then “converted” to forward-facing use after that. This single seat spans both rear and forward stages.

Booster seat

A belt-positioning booster seat must be used when a child outgrows their convertible seat but is still too small for an adult seatbelt. Typically this is between ages 4-12, depending on size. Boosters raise kids up so belts fit properly.

So in total, you’ll usually need one infant seat and convertible seat to cover the baby/toddler stages, then two boosters once both kids transition to forward-facing. Of course twins will need two infant seats upfront. Some “all-in-one” seats now span all the way from infancy through boostering with one purchase.

Do you need two infant car seats?

Yes, if you have twins or two infants close in age, you will need two rear-facing infant seats. An infant seat is required by law for all babies under 1 year old in every state. It is not possible to safely secure two infant car seats in one base or share one seat.

There are a few options when needing two infant seats:

Buy two identical seats

Many parents choose to buy two of the same infant seat model and base for simplicity. This ensures full compatibility with dual strollers and lets you freely swap seats between vehicles. It’s easiest if you’ll be transporting the babies together often.

Buy different compatible seats

You can also opt for two infant seats that are different models but within the same brand family, like Chicco KeyFit 30 and Chicco Fit2. These will have matching attachment points to lock together onto double strollers.

Buy any two seats

If you’ll rarely be moving both infant seats at once, you can simply buy any two compatible infant car seats you like. Just be sure to get two bases, one for each vehicle. This gives you more flexibility to choose different features.

No matter what route you take, check that both seats meet current safety standards, fit in your vehicles correctly, and accommodate newborns. Having two seats on hand lets you immediately secure both babies on their very first car ride home!

Do you need two convertible car seats?

In most cases, yes – once infants outgrow their rear-facing seats around age 1-2, you’ll need to buy two convertible seats to replace them. Here’s why:


All states require children to remain rear-facing until at least age 2. Many states are now updating laws to require rear-facing until age 4. Children cannot legally sit forward-facing before meeting minimum age, weight, and height requirements. Two convertibles allow both kids to stay rear-facing per car seat laws.


The AAP recommends keeping kids rear-facing as long as possible, up to the convertible seat limits (usually 40-50 lbs). Again, this protects vulnerable spines and necks. Two seats let you maximize safety and follow medical guidance.


Trying to use one convertible for two growing toddlers rarely works well. Their differing sizes and leg room needs make sharing very uncomfortable. Two convertibles optimized for each child’s current measurements are best.


It’s difficult to swap one convertible back and forth between vehicles every trip. Dual convertibles mean each child always has a familiar seat ready in mom’s car or dad’s car.

So while convertibles can often last 8-10 years through both rear and forward stages, you need two seats once infants outgrow their first seats. This enables both children to remain rear-facing for optimal safety.

Do you need two booster seats?

Yes, once both children have outgrown their convertible seats and need to transition to belt-positioning boosters, two seats must be used. Here’s why:

Safety requirements

All states have laws requiring booster seats for children who have outgrown convertible seats but are still too small to safely use adult seatbelts alone. Children must remain in boosters until at least age 8-12 and 4’9″ tall.

Seat belt fit

Vehicle seat belts do not properly fit most kids until they are over 4’9″ tall. Boosters position lap and shoulder belts for correct fit. Children too small for adult belts can suffer severe intestinal, spine, and neck injuries without a booster. Two seats allow appropriate belt positioning.


Responsible maturity is required to remain seated properly at all times in a seat belt alone. Young kids may slouch, twist, or place seat belts incorrectly. Boosters help remind children to stay upright and positioned correctly.

For families with twins or siblings close in age, having two booster seats prevents any gaps in protection as both kids grow. Drivers can face fines for failing to provide required booster seats. Kids can focus better whencomfortably seated in their own spaces.

Should twins share a car seat?

Twins should never share a car seat, even identical twins. All babies under 1 year must be secured in their own rear-facing infant seats. After that stage, the above reasons still apply:

  • Safety – Twins need optimal positioning and fit for their individual bodies in crashes.
  • Comfort – Twins will pinch and distract each other sharing tight spaces.
  • Legality – State laws require separate approved seats for each child.
  • Rotation – Each twin needs a familiar seat ready in each vehicle.

While buying two of everything can be costly upfront, correctly restraining twins in separate car and booster seats through each transition is essential. This ensures their growing bodies are fully protected as safe, independent passengers.

What if you can’t afford two seats?

If truly unable to afford purchasing two car seats, there are some options to obtain seats:

  • Borrow from friends or family temporarily
  • Rent seats from hospitals, nonprofits, and community centers
  • Inquire about free/reduced seats from local fire/police departments
  • Check for seat giveaways and trade-ins at retailers
  • Search for subsidized seats from government agencies

The goal should be finding two seats – even if mismatched – to avoid compromising safety. Kids can rotate seats as needed until proper restraints for both can be purchased. Fundraisers, classified ads, and budgeting may help fill in gaps.


Outside of occasional unavoidable exceptions, each child must be properly buckled in their own car seat, infant seat, convertible seat, or booster seat. Although buying two seats per child can get expensive, it is a necessary investment in their protection. Correct use of appropriate seats drastically reduces injury and death. Two seats also provide needed space and comfort. Following car seat laws and safety recommendations requires having a seat for each child.

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