Sizing

Hat size calculator

Pick a size to see the head circumference and hat height, then add your gauge to get the cast-on with the right negative ease, rounded to your rib.

Size

Sts per 4 in

Rows per 4 in

Rib multiple

Your result

Adult woman: head and hat height22.5 in (57 cm) head11 in (28 cm) tall

Add your stitch gauge for the cast-on.

Hat sizes: head circumference and hat height
Size	Head	Hat height
Preemie (3–4 lb)	11 in / 28 cm	4 in / 10 cm
Preemie (5–6 lb)	13 in / 33 cm	5 in / 13 cm
Newborn	14 in / 36 cm	6 in / 15 cm
Baby, 3–6 months	17 in / 43 cm	7 in / 18 cm
Baby, 6–12 months	18 in / 46 cm	7.5 in / 19 cm
Toddler, 1–3 years	19 in / 48 cm	8 in / 20 cm
Child, 3–10 years	20 in / 51 cm	8.5 in / 22 cm
Teen	21 in / 53 cm	10 in / 25 cm
Adult woman	22.5 in / 57 cm	11 in / 28 cm
Adult man	23.5 in / 60 cm	11.5 in / 29 cm

Head sizes are averages. Measure the wearer if you can.

Hat size chart: head circumference and hat height from preemie to adult man. Free to print and save.

How to use it

Choose the size, or measure the wearer's head just above the ears.
Enter your stitch and row gauge per 4 inches from a washed swatch.
Cast on the stitches shown and work to the hat height before the crown.

Questions

What size should a knitted hat be?

About 10% smaller around than the head, so it stretches to fit. For a 22.5 inch adult head that's a hat about 20 inches around.

How tall should a hat be?

From the brim to the top of the crown: about 11 inches for an adult woman, 6 inches for a newborn. Add 2 to 3 inches for a folded brim or a slouchy hat.

What's an average adult head size?

About 21 to 23 inches for women and 22 to 24 inches for men, so most adult hats are made for 22 to 23 inches.