Crochet Hat Sizes Chart: Head Circumference and Hat Height by Age
Head circumference, hat circumference and hat height for preemies to adults, plus the crown-diameter formula and how much negative ease to use for a snug crochet hat.
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In this post
The most common reason a crochet hat doesn't fit isn't the pattern — it's the size. Use this chart to choose the right circumference and height, then the formula below to check your crown as you work.
Heads vary, so these are average ranges. When you can, measure the actual head around the forehead, just above the ears.
The rest of this post is just below — free, as always.
Hat size chart
| Age | Head circumference | Hat height (crown to brim) |
|---|---|---|
| Preemie | 10–12 in (25–30 cm) | 4 in (10 cm) |
| Newborn | 13–14 in (33–36 cm) | 5–6 in (13–15 cm) |
| 3–6 months | 14–17 in (36–43 cm) | 6½ in (16.5 cm) |
| 6–12 months | 16–19 in (41–48 cm) | 7 in (18 cm) |
| Toddler (1–3 years) | 18–20 in (46–51 cm) | 7½–8 in (19–20 cm) |
| Child (3–10 years) | 19–20½ in (48–52 cm) | 8–9 in (20–23 cm) |
| Teen | 20½–22 in (52–56 cm) | 9–10 in (23–25 cm) |
| Adult woman | 21½–22½ in (55–57 cm) | 9½–11 in (24–28 cm) |
| Adult man | 22–24 in (56–61 cm) | 10–11½ in (25–29 cm) |
Add 2–3 in to the height for a slouchy hat or a folded brim.
Negative ease: make the hat smaller than the head
A hat that's exactly head-sized will slip down. Most crochet hats are made 1–2 in (2.5–5 cm) smaller than the head, so the stretch holds them in place. Very stretchy ribbing can take more; stiff cotton needs less.
The crown formula
When you work a hat top-down, the flat circle at the top should reach this diameter before you stop increasing:
Crown diameter = hat circumference ÷ 3.14
Example: for a 20-in hat, stop increasing when the circle measures about 6⅓ in across (20 ÷ 3.14). Lay it flat and measure through the centre.
Hat patterns to use with this chart
- Beginner beanie
- Baby hat (newborn to 12 months)
- Santa hat (toddler to adult)
- Bucket hat
- Balaclava
Common questions
What size should a crochet adult hat be?
For an average adult head of 22 in, make the hat about 20–21 in around and 9½–11 in tall.
What size is a newborn crochet hat?
About 12–13 in around (for a 13–14 in head) and 5–6 in tall.
How do I fix a hat that's too big?
Pull back to the crown and remove one increase round, or go down a hook size. For a small difference, add a tighter ribbed brim with a smaller hook.
Bookmark this chart for every hat you make. 🧢
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