This pattern has the instructions for 9 sizes, starting from newborn to adult large size. The finished hat has some stretch but if you prefer a loose fit, simply use a larger hook

Materials needed:
• 3.5 mm (E) Hook for 0-6 months and 6-12 months sizes
• 4.0 mm (G) Hook for 3-6 months, 9-12 months and child sizes
• 4.5 mm (US7) Hook for toddler size
• 5 mm (H) Hook for teen and small adult size
• 5.5 mm (I) or 6 mm (J) Hook for medium to large adult size
• Approximately 80-200 yards (40-90 grams) of worsted/aran
weight yarn (I used Paintbox Yarns Simply Aran and Aldi So
crafty Aran yarn), depending on the size chosen.
• Yarn needle for weaving in ends
• Scissors
• Optional: Faux fur pompom

Gauge:
• 3.5 mm (E) Hook: 5 DC = 1”
• 4.0 mm (G) Hook: 4 DC = 1”
• 4.5 mm (US7) Hook: 6 DC = 1.5”
• 5 mm (H) Hook: 6 DC = 1.5”
• 5.5 mm (I) Hook: 7 DC = 2”
• 6 mm (J) Hook: 5 DC = 1.5”