Car seat & booster law
Missouri
Verified · JUN 2026Quick answer · Missouri
A car seat or booster is required until your child is 8 years old or taller than 4'9".
Children under 4, or under 40 pounds, must be in a car seat. Children 4 to 7 who weigh 40 to 79 pounds and are under 4 feet 9 inches must be in a car seat or booster. A child 80 pounds or over 4 feet 9 inches may use a seat belt.
Car seat law checker
The legally required restraint, by state.
General information, not legal advice.
SeatCheckerRequired vs recommended
What the law enforces, and what pediatricians advise. They are not the same.
The law requires
Minimum, or it's enforceable
- Rear-facing until
- Not specified by law
- Booster until
- Age 8 or 4'9"
- Back seat
- Not required
Pediatricians recommend
AAP — safer, not the law
- Rear-facing until
- To seat limit (often age 2+)
- Booster until
- 4'9" — typically age 8–12
- Back seat
- Until age 13
AAP guidance is a safety best practice and is separate from Missouri's legal minimum, which uses an 80-pound weight cutoff. Pediatricians recommend a booster until the seat belt actually fits.
Every stage, by the law
Dual units shown throughout (in + cm, lb + kg). Rows marked Guidance are best practice, not a statutory requirement in Missouri.
| Stage | Age | Height | Weight | Citation |
|---|---|---|---|---|
| Rear-facing | Infant (per seat) | — | — | Guidance |
| Forward-facing | Toddler (per seat) | — | — | Guidance |
| Booster | until 8 yr | < 4'9" / 145 cm | — | Mo. Rev. Stat. § 307.179 |
| Seat belt | 8 yr + | or ≥ 4'9" / 145 cm | — | Mo. Rev. Stat. § 307.179 |
| Back seat | Recommended < 13 | — | — | Guidance |
- Age
- Infant (per seat)
- Age
- Toddler (per seat)
- Age
- until 8 yr
- Height
- < 4'9" / 145 cm
- Age
- 8 yr +
- Height
- or ≥ 4'9" / 145 cm
- Age
- Recommended < 13