Many car seats are rated for newborns as small as 5 pounds but that doesn’t always mean that they’ll provide a safe fit. When selecting a seat, it’s important to look at the harness heights, along with the weight ratings. Our beautiful model, Piper was 3 weeks old, approximately 9 pounds & 21″ long. The top picture was her in an Alpha Omega Elite. The bottom picture was in a SureRide. The difference was remarkable!