FMVSS 213 Child Restraint System: Testing, Labels, and 213b Switch

Federal Motor Vehicle Safety Standard 213, known as FMVSS 213, is the federal rule that sets how every child car seat, infant carrier, and booster sold in the United States must be built, crash-tested, and labeled. The National Highway Traffic Safety Administration (NHTSA) writes and enforces it, and it covers restraints intended for children up to 80 pounds. The current version applies to seats manufactured before December 5, 2026. After that date, a revised standard called FMVSS 213b takes over with updated crash tests, new test dummies, and revised labeling rules.1eCFR. 49 CFR 571.213 – Child Restraint Systems

What Seats FMVSS 213 Covers

The standard reaches any device marketed to restrain, seat, or position a child weighing 36 kilograms (80 pounds) or less in a passenger car, multipurpose passenger vehicle, truck, or bus. It also covers child restraints intended for use in aircraft. Rear-facing infant carriers, convertible seats, forward-facing harness seats, and belt-positioning boosters are all in scope.1eCFR. 49 CFR 571.213 – Child Restraint Systems

Two carve-outs are worth knowing. Type I and Type II vehicle seat belts on their own are not covered, and separate provisions apply to restraints designed for children with physical disabilities. Beyond those, every child restraint sold in the country must comply regardless of price or where it is sold. Federal law makes it illegal to manufacture, sell, or import motor vehicle equipment that fails to meet an applicable safety standard.2Office of the Law Revision Counsel. 49 USC 30112 – Prohibitions on Manufacturing, Selling, and Importing Noncompliant Motor Vehicles and Equipment

The 2026 Switch to FMVSS 213b

FMVSS 213 governs seats manufactured before December 5, 2026. On that date, FMVSS 213b becomes the controlling rule for anything built afterward. Seats made before the cutoff and already on store shelves remain legal to sell and use.1eCFR. 49 CFR 571.213 – Child Restraint Systems

The revision is substantive. FMVSS 213b uses an updated test bench designed to reflect the interior geometry of a modern vehicle, replaces some older crash-test dummies with newer ones, and requires that most restraints be tested with a simulated lap-and-shoulder belt rather than a lap belt alone.3eCFR. 49 CFR 571.213b – Standard No. 213b; Child Restraint Systems

Some practical minimums tighten. Manufacturers can no longer recommend forward-facing use for children under 12 kilograms (about 26.5 pounds), and boosters cannot be recommended for children under 18 kilograms (about 40 pounds).4Federal Register. Federal Motor Vehicle Safety Standards; FMVSS No. 213, FMVSS No. 213a, FMVSS No. 213b – Response to Petitions for Reconsideration Labeling rules give manufacturers more flexibility in wording and pictograms to communicate the height and weight range for each mode. The mail-in registration card must now carry a field for the owner’s phone number so recall notices reach parents faster.3eCFR. 49 CFR 571.213b – Standard No. 213b; Child Restraint Systems

How Car Seats Are Tested

The heart of FMVSS 213 compliance is dynamic sled testing. A child restraint is mounted on a specialized frontal-impact seat assembly, and the sled decelerates at a velocity change of 48 kilometers per hour (30 miles per hour) to simulate a head-on crash.5National Highway Traffic Safety Administration. Laboratory Test Procedure for FMVSS 213 Child Restraint Systems Anthropomorphic test dummies representing children of different sizes ride in the seat, and sensors record what would happen to a real child’s head, chest, and limbs during the impact.

Three measurable limits determine whether a seat passes:

  • The Head Injury Criterion (HIC), calculated over a 36-millisecond window, must not exceed 1,000. This value captures the severity and duration of head acceleration and correlates to skull fracture and brain injury risk.
  • The resultant acceleration at the dummy’s upper torso cannot exceed 60 g’s, except for intervals totaling no more than 3 milliseconds.5National Highway Traffic Safety Administration. Laboratory Test Procedure for FMVSS 213 Child Restraint Systems
  • Head excursion is capped at 720 millimeters (about 28 inches) forward of a reference point on the test bench in some configurations, and 813 millimeters (32 inches) in others.5National Highway Traffic Safety Administration. Laboratory Test Procedure for FMVSS 213 Child Restraint Systems

The harness buckle has its own test. It must stay locked during the crash but still open easily enough afterward for an adult to free the child. FMVSS 213 sets a release-force window for pre-impact and a maximum post-impact release force, because a buckle that jams after a crash can trap a child in a burning or submerged vehicle.5National Highway Traffic Safety Administration. Laboratory Test Procedure for FMVSS 213 Child Restraint Systems

Manufacturers typically run hundreds of internal tests on a design before certification. No seat reaches retail without meeting every benchmark. NHTSA also buys child restraints off store shelves and tests them independently, opening a compliance investigation if a product fails.

Side Impact Testing Under FMVSS 213a

FMVSS 213a is the companion rule addressing crashes where a vehicle is struck from the side, which produce different forces than frontal collisions. Every restraint subject to 213a must also meet all applicable requirements under FMVSS 213.6eCFR. 49 CFR 571.213a – Standard No. 213a; Child Restraint Systems – Side Impact Protection The test uses a Q3s dummy, a 3-year-old-sized device originally developed in Europe with head accelerometers, a chest deflection sensor, and other instrumentation to measure lateral forces.7Federal Register. Anthropomorphic Test Devices; Q3s 3-Year-Old Child Side Impact Test Dummy

The bench simulates a modern vehicle’s rear seat geometry, and the impact replicates a perpendicular strike. Injury criteria center on HIC over a 15-millisecond window and chest deflection. Energy-absorbing materials in the seat’s side wings play a large role in meeting the limits. Under 213b, side impact testing expands to include the CRABI 12-month-old dummy for restraints covering children in the 22-to-30-pound range.4Federal Register. Federal Motor Vehicle Safety Standards; FMVSS No. 213, FMVSS No. 213a, FMVSS No. 213b – Response to Petitions for Reconsideration

Labels, Registration, and Recalls

Every child restraint sold in the United States must carry permanent labels with specific information. The absence of these labels is one of the fastest ways to identify a non-compliant seat.3eCFR. 49 CFR 571.213b – Standard No. 213b; Child Restraint Systems The labels must include:

  • The exact statement “This child restraint system conforms to all applicable Federal motor vehicle safety standards.”
  • An aircraft-certification statement in red lettering. Seats approved for aircraft use read “This Restraint is Certified for Use in Motor Vehicles and Aircraft.”8Federal Aviation Administration. AC 120-87C – Use of Child Restraint Systems on Aircraft
  • The manufacturer’s name, address, model number, and date of manufacture.
  • The U.S. Government Vehicle Safety Hotline number (1-888-327-4236) and the NHTSA website.
  • The weight and height range the seat is designed for.
  • An airbag warning on any seat that can be used rear-facing, in specified font sizes and high-contrast colors.

Clear installation and use instructions must also be permanently attached to the seat, separate from any manual in the box. A postage-paid registration card addressed to the manufacturer must ship with every restraint so the company and NHTSA can reach owners if a defect surfaces later.3eCFR. 49 CFR 571.213b – Standard No. 213b; Child Restraint Systems Parents can also check for active recalls anytime through NHTSA’s recall search at nhtsa.gov/recalls.9National Highway Traffic Safety Administration. Check for Recalls – Vehicle, Car Seat, Tire, Equipment

Installation: LATCH, Vehicle Belts, and Aircraft Use

FMVSS 213 requires most add-on child restraints (other than car beds, harnesses, and belt-positioning boosters) to include hardware that attaches to the lower anchorages defined in the companion rule FMVSS 225.1eCFR. 49 CFR 571.213 – Child Restraint Systems This is the LATCH system (Lower Anchors and Tethers for Children). The vehicle-side anchors are two horizontal bars built to precise diameter and length specifications.10eCFR. 49 CFR 571.225 – Standard No. 225; Child Restraint Anchorage Systems

Seats must also be installable with a vehicle’s three-point lap-and-shoulder belt. That dual compatibility matters in daily life. Older vehicles may lack LATCH anchors, and LATCH lower anchors have weight limits that vary by manufacturer. Once the combined weight of the child and seat exceeds the limit printed in the seat’s manual, the seat has to be installed with the vehicle belt instead.

Aircraft use follows the label. A seat marked “This Restraint is Certified for Use in Motor Vehicles and Aircraft” may be used on commercial flights during ground movement, takeoff, and landing.8Federal Aviation Administration. AC 120-87C – Use of Child Restraint Systems on Aircraft If the label reads “This Restraint is Not Certified for Use in Aircraft,” the airline will not allow it on board. Booster seats that rely on a vehicle lap-and-shoulder belt do not qualify for aircraft use because airplane seat belts are lap-only.

How to Spot a Non-Compliant or Counterfeit Seat

Counterfeit and unregulated child restraints show up regularly on online marketplaces, especially from overseas sellers. They can look nearly identical to compliant models but fail in crashes because they were never designed to pass FMVSS 213 testing. The fastest check is the compliance label: if a seat lacks the statement “This child restraint system conforms to all applicable Federal motor vehicle safety standards,” it is almost certainly non-compliant.

Other warning signs:

  • No instruction manual and no registration card.
  • A three-point harness instead of the five-point harness (two shoulder straps, two hip straps, crotch buckle) that compliant seats use.
  • An all-plastic buckle. Legitimate buckles use metal internal components.
  • Harness webbing that is noticeably narrow or flimsy compared with a vehicle seat belt.
  • Grammatical errors or awkward translations on warning labels.
  • Plastic that flexes easily by hand or a carrier-to-base connection that feels fragile.

Seats built to a foreign standard are not automatically legal in the United States. Products certified to the European ECE R44 or R129 (i-Size) rules must be separately certified to FMVSS 213 before they can be sold here. A seat bought during international travel and brought home may never have been crash-tested under U.S. conditions.

Penalties for Selling Non-Compliant Seats

NHTSA can order a mandatory recall when a seat fails compliance testing, requiring the manufacturer to notify every registered owner and provide a free remedy. Civil penalties reach up to $27,874 per violation, and each non-compliant seat counts as a separate violation, with a cap of $139,356,994 for a related series.11eCFR. 49 CFR Part 578 – Civil and Criminal Penalties NHTSA also works with Customs and Border Protection to intercept non-compliant restraints before they reach U.S. stores.