Most rear-facing infant seats will fit a child less than 22 pounds.
Most rear-facing convertible seats will fit a child from 5 to 35 pounds.
Children should remain rear-facing until reaching the upper weight limit of their seat.
Most forward-facing convertible seats will fit a child up to 40 pounds.
Most forward-facing only seats with harness will fit a child up to at least 40 pounds.
Child safety seat harness limits have increased considerably on some models, because research shows children are safest in a harness. Some limits are as much as 65 pounds; check the labels on your seat.
Belt positioning boosters (without a harness) will fit a child up to 80 pounds; although, some newer booster seats have an upper weight limit of 100 pounds.
These are only guidelines. Always consult the owner’s manual for your specific seat and vehicle and follow the manufacturer’s recommendations.