Hat fits loosely on a 3-year old with the brim turned up. But with the brim turned down, it will easily fit him or her into adulthood. It even stretches over my 23” head.

Needles used:

Size 2 US - Ribbing

Size 3 US - Everything else

This is my very favorite tubular cast on (in the round) demonstrated by Suzanne Bryan. It’s super stretchy and very easy:

Video Tutorial - Simple Fitted Hat Crown Decreases

The Neatest Jogless Join for Wide Stripes Knit in the Round