Crochet Hat Size Chart
Standard hat sizes from preemie to large adult, plus the crown math to turn any head measurement into a starting stitch count.
| Size | Head circ. | Crown diameter | Hat height |
|---|---|---|---|
| Preemie | 12" / 30.5 cm | 3.75" / 9.5 cm | 4.5" / 11.5 cm |
| Newborn (0-3 mo) | 14" / 35.5 cm | 4.5" / 11.5 cm | 5.5" / 14 cm |
| Baby (3-6 mo) | 15" / 38 cm | 4.75" / 12 cm | 6" / 15 cm |
| Baby (6-12 mo) | 16.5" / 42 cm | 5.25" / 13.5 cm | 6.5" / 16.5 cm |
| Toddler (1-3 yr) | 18" / 46 cm | 5.75" / 14.5 cm | 7" / 18 cm |
| Child (3-10 yr) | 19.5" / 49.5 cm | 6.25" / 16 cm | 7.5" / 19 cm |
| Teen / Small Adult | 21" / 53 cm | 6.75" / 17 cm | 8" / 20.5 cm |
| Adult | 22" / 56 cm | 7" / 18 cm | 8.5" / 21.5 cm |
| Large Adult | 23" / 58.5 cm | 7.5" / 19 cm | 9" / 23 cm |
How the crown calculator works
- Apply negative ease. Fit circumference = head circumference x (1 + ease / 100). A 22-inch head at minus 10 percent gives 22 x 0.9 = 19.8 inches.
- Get the crown diameter. Diameter = fit circumference / pi = 19.8 / 3.1416 = 6.3 inches. Stop increasing when your flat circle measures that across.
- Convert to stitches. Crown stitches = fit circumference x stitch gauge, rounded up to an even number: 19.8 x 4.5 = 89.1, so 90 stitches.
Hat sizing FAQ
How much negative ease should a crochet hat have?
Crochet fabric stretches less than knit, so 1 to 2 inches (about 5 to 10 percent) of negative ease is the usual target. A 22-inch head is typically worked at 20 to 21 inches around. The calculator applies minus 10 percent by default and you can change it.
Why does the crown diameter equal head circumference divided by pi?
A hat crown is crocheted as a flat circle, and the edge of that circle becomes the hat circumference. Circumference = pi x diameter, so diameter = circumference / pi. A 19.8-inch fit circumference gives a 6.3-inch crown.
Are these hat sizes standard?
The table follows the Craft Yarn Council head circumference ranges, which most published hat patterns use. Heads vary, so for gifts measure the wearer when possible and pick the closest row.
What gauge should I enter for the crown calculator?
Crochet a small flat circle or a few rounds in your chosen stitch, then count how many stitches fit in one inch across a round. That stitch-per-inch number times the fit circumference is the stitch count where you stop increasing.