Booster seats expire because the materials they’re made from degrade over time, and because safety standards evolve faster than most parents realize. Most booster seats have a useful life of 6 to 10 years from the date of manufacture, depending on the brand. After that window, the seat may no longer protect your child the way it did when it was new.
Plastics and Foam Break Down Over Time
The plastic shell of a booster seat is its structural backbone. It’s what absorbs and redirects crash forces. But plastic doesn’t stay the same forever. Years of temperature swings inside a car, where summer heat can push interior temperatures well above 150°F, cause the polymer chains in the plastic to weaken. This process, called thermal cycling, makes the shell more brittle and more likely to crack or shatter on impact rather than flexing and absorbing energy the way it was designed to.
UV exposure accelerates the problem. Even with tinted windows, sunlight breaks down the molecular structure of polycarbonate and high-density polyethylene, the two plastics most commonly used in seat shells. The foam padding inside the seat also compresses and hardens over years of use, reducing its ability to cushion a child during a collision. None of these changes are visible to the naked eye. A booster seat that looks perfectly fine can have significantly compromised structural integrity.
Safety Standards Keep Getting Stricter
Federal safety requirements for child restraints don’t stand still. The standard governing car seats and boosters, known as FMVSS 213, has been updated multiple times, and a major recent change illustrates how dramatically the bar can shift. In 2022, NHTSA finalized a new rule (FMVSS 213a) that for the first time requires side impact testing for child restraints designed for kids weighing up to 40 pounds or up to about 43 inches tall. Before this rule, there was no federal side impact requirement at all.
The testing itself became more sophisticated. NHTSA adopted a purpose-built crash test dummy called the Q3s, designed specifically to measure side impact forces on a 3-year-old child’s body. It was the agency’s first child dummy engineered for side impacts. The new test simulates a vehicle-to-vehicle side crash, including a door intruding into the passenger space, something no previous federal test had replicated. A booster seat manufactured before these standards existed was never designed or tested to meet them.
This is the core regulatory reason for expiration dates. A seat built in 2016 met 2016 rules. A seat built in 2024 reflects nearly a decade of additional crash research, material science, and dummy technology. Expiration dates give manufacturers a mechanism to cycle older designs out of use as the science moves forward.
How Long Different Seats Last
Expiration timelines vary by brand and seat type. Graco, one of the largest manufacturers, sets a 10-year useful life for belt-positioning boosters and steel-reinforced car seats, and a 7-year useful life for plastic-reinforced models. The difference reflects how well the internal structure holds up: steel reinforcement degrades more slowly than an all-plastic frame.
Other major brands fall in a similar range. Most belt-positioning boosters land between 6 and 10 years. Combination seats that convert from a harnessed seat to a booster sometimes have shorter lifespans because they have more moving parts and mechanical components that wear out. The expiration date is always calculated from the date of manufacture, not the date you bought or started using the seat. A booster that sat in a warehouse or on a store shelf for two years has already used up part of its useful life before your child ever sits in it.
How to Find the Expiration Date
Every booster seat sold in the U.S. has its manufacture date and either an expiration date or a “do not use after” date marked somewhere on the seat itself. The most common locations are the bottom of the seat, the back of the shell, or molded directly into the plastic. Some manufacturers use a printed label, while others stamp the date into the shell so it can’t peel off or fade. If the seat has a detachable base, check both the base and the seat portion, as they may have separate dates.
If you can’t find a date on the seat, the manufacturer’s website will typically let you look up your model number to determine its useful life. The instruction manual also lists this information, though most parents have lost it by the time expiration becomes relevant.
What Happens If You Use an Expired Seat
No federal law specifically prohibits using an expired booster seat. However, most state child passenger safety laws require that children be restrained “according to the manufacturer’s instructions.” Colorado’s law, for example, requires proper restraint per the manufacturer’s guidelines for all children under 9. Since the manufacturer’s instructions include an expiration date and a clear statement not to use the seat beyond it, using an expired seat could put you out of compliance with your state’s law even if the statute doesn’t mention expiration directly.
In the event of a crash, an expired seat also creates a gray area for insurance claims. If an insurer determines that a child was in a restraint the manufacturer had declared past its useful life, it could complicate injury claims. More practically, if the seat fails in a crash because degraded plastic cracked or foam didn’t absorb impact properly, the manufacturer has no liability. The expiration date is effectively the end of their safety guarantee.
What to Do With an Expired Booster Seat
The worst thing you can do with an expired seat is donate it or sell it. Secondhand booster seats are one of the main ways expired restraints stay in circulation, and a buyer at a yard sale has no easy way to assess whether a seat is still within its useful life, especially if labels have faded.
Target runs a recurring car seat trade-in event, typically twice a year, where you can drop off any old car seat or booster at a participating store and receive 20% off a new seat, stroller, or select home gear. The collected seats go to recycling partners who break them down into raw materials. Since the program started, over 3.5 million car seats have been recycled, diverting more than 1.25 million pounds of plastic from landfills since 2022 alone. Some of that recycled plastic ends up in Target’s own store-brand products.
If no trade-in event is available near you, the standard recommendation is to cut the harness straps (if any), remove the padding, and write “EXPIRED, DO NOT USE” on the shell in permanent marker before putting it in the trash. This prevents anyone from pulling it out and reusing it.