They fit my 18-month-old now but will probably be outgrown in 6-8 months. He's 25 lbs, size 6 shoe. Picture for comparison, the green stripes are 12-24 month sized from Carters. The yellow socks are "2T-4T" from Kohls. My only concern is that he likes picking at the dots, I'm worried after a few washes he'll get one off and eat it. I'll have to keep an eye on them. But they are very grippy!