Match the car seat to your baby's age, weight, and height

Check your baby's current weight and height against the car seat manufacturer's limits before purchasing. Car seats are designed for specific size ranges, and using one outside those limits compromises crash protection. Your pediatrician records these measurements at every well-child visit.

Why It Works

The NHTSA and AAP base car seat recommendations on a child's size rather than age alone, because children grow at different rates. A seat that fits properly keeps the harness positioned correctly over the strongest parts of the body (shoulders and hips), distributing crash forces safely.

Tips

• Rear-facing infant seats typically fit from 4-35 lb depending on the model; check both weight and height limits
• Move to the next seat stage when your child reaches either the weight or height maximum -- whichever comes first
• The AAP recommends keeping children rear-facing as long as possible, ideally until they reach the rear-facing limits of their convertible seat
• Premature or small babies may need a car bed or special seat validated for their size -- ask your pediatrician
• Never go by age alone; a large 6-month-old and a small 6-month-old may need different seats