Every state has a child passenger safety law, but the exact age, height, and weight a child must reach before leaving a booster seat varies from state to state. Federal law sets how car seats and boosters are built and crash tested, while each state decides when a child must use one. This guide explains the general rules and links to a dedicated guide for every state’s exact requirements.
Subscribe
Get new articles by email when we publish.
How Federal and State Law Divide This Topic
Federal Motor Vehicle Safety Standard 213, defined in 49 CFR 571.213, sets the manufacturing and crash test requirements every child restraint sold in the United States must meet. A newer standard, FMVSS 213b, becomes mandatory for restraints manufactured on or after December 5, 2026, adding stronger side impact and frontal crash requirements. Federal regulation bars manufacturers from marketing a booster for a child under 30 pounds, but it sets no federal age or height rule for when a child must actually use one.
States fill that gap by passing their own usage laws. According to the Governors Highway Safety Association’s compilation of state child passenger safety laws, every state, the District of Columbia, and US territories require some form of child restraint until a child reaches a certain age, height, or weight, then generally shift to a booster seat requirement until the child is large enough for an adult seat belt to fit properly. The specific numbers in that law are set entirely by each state legislature, which is why the age a child can stop using a booster differs depending on where they live.
How Booster Seat Laws Vary by State
State booster seat laws generally follow the same structure: a minimum age or size at which a booster becomes required, and a maximum age, height, or weight at which the child may move to an adult seat belt alone. What differs is where each state sets those two points. Some states set the booster exit age around 6, others extend it to 8 or 9, and a few tie the requirement to height, commonly around 4 feet 9 inches, rather than age alone.
This variation is not a technicality. Multiple states have raised their booster requirements in the past two years, including updated laws in Michigan, Colorado, and Montana, and additional states have changes scheduled to take effect in 2026 and 2027. A booster seat law that was accurate for a state last year may no longer reflect the current requirement, which is why this guide links to a dedicated, regularly checked page for each state rather than listing every number in one place.
Legal Minimum Versus Safety Recommendation
The age or height written into state law is a legal floor, not a safety endorsement. The Centers for Disease Control and Prevention’s booster seat guidance reports that booster seats reduce the risk of serious injury by 45 percent for children ages 4 through 8 compared with a seat belt alone, and most children do not fit an adult seat belt correctly until somewhere between ages 9 and 12. The American Academy of Pediatrics recommends keeping a child in a booster until they reach about 4 feet 9 inches tall, regardless of what the local legal minimum happens to be.
The more reliable test is not a birthday but fit. A child is ready for a seat belt alone only when the lap belt sits low across the thighs, the shoulder belt crosses the chest rather than the neck, the child’s knees bend naturally at the edge of the seat, and the child can sit that way for the entire trip without slouching. A child who has legally aged out of their state’s booster requirement but still fails this test is safer staying in a booster.
Which State’s Law Applies When You Travel
Child restraint law follows the road you are driving on, not the state where you live. A family that legally moves a child out of a booster under their home state’s rule may become non-compliant the moment they cross into a neighboring state with a stricter requirement, even in a rental car. For example, a child who can legally ride with just a seat belt at age 6 in one state may still be required to use a booster in a neighboring state that sets the exit age at 8, and the stricter state’s law governs while driving there. Families who travel or move between states should check the booster seat requirement for every state on their route, not only their home state.
Common Exemptions
Several categories of vehicles are commonly treated differently under state child restraint laws, though the exact exemption varies by state. Taxis and rideshare vehicles are exempt from the booster requirement in some states but not others. School buses are generally exempt from the booster and seat belt laws that apply to passenger vehicles, since they are built with different safety standards. Rental cars are not exempt simply because the family is traveling; the booster requirement of the state being driven in still applies. Because these exemptions differ by state, families should verify the specific rule where they are driving rather than assuming an exemption applies everywhere.
Fines and Penalties Vary by State
States set their own penalties for failing to properly restrain a child passenger, and the range is wide. Reported first offense fines for a child restraint violation generally fall between $10 and $500 depending on the state, and some states add points to the driver’s license in addition to the fine. Because the amount and structure of the penalty is set individually by each state legislature, it should be confirmed on that state’s own guide rather than assumed to match a neighboring state.
Recent and Upcoming Changes to Booster Seat Laws
Several states have updated their child passenger safety laws recently, and more changes are scheduled. Michigan’s updated law took effect in April 2025. Colorado raised its booster requirement effective January 2025. Montana expanded its requirement effective October 2025. California passed a law updating its restraint standard that becomes operative in 2027. At the federal level, according to the National Highway Traffic Safety Administration, FMVSS 213b becomes mandatory for newly manufactured restraints on December 5, 2026. Because state legislatures revisit these laws regularly, the guide for each state is checked and updated on its own schedule to reflect the current requirement.
What Each State Guide Covers
Every state’s dedicated booster seat law guide on this site covers the exact statute, the specific age, height, or weight cutoff that state has set, the current fine range, whether the state has a rear seat requirement, and any exemptions that state recognizes. This guide and every state page linked from it are written and personally verified by Axad Malik against official state and federal sources. Select a state below to see its current requirement in full.
Disclaimer
This article is for general informational purposes only. It is not legal advice. Lawwalls publishes informational content only and does not provide legal services or legal advice. For legal advice about your specific situation contact a licensed attorney in your state. Laws change and vary by jurisdiction. Verify current rules with official government sources or a qualified lawyer.