Hat Cast-On Calculator
How many stitches to cast on for a knitted hat, plus the crown decreases.
Craft Yarn Council head circumference chart, midpoint of each range.
Sets a typical stockinette gauge. Swatch and enter your own for accuracy.
Used for crown depth.
10% is standard; 5–15% typical.
The cast-on rounds to the nearest multiple so the pattern repeats evenly.
Hat height is the total crown-to-brim length, unfolded. Add 2–3″ if you want a folded brim. Presets reset the height; you can then change it.
- Round 1 (set-up): *K23, k2tog; repeat from * 4 times. 96 sts.
- Round 2: Knit.
- Round 3: *K10, k2tog; repeat from * 8 times. 88 sts.
- Round 4: Knit.
- Round 5: *K9, k2tog; repeat from * 8 times. 80 sts.
- Round 6: Knit.
- Round 7: *K8, k2tog; repeat from * 8 times. 72 sts.
- Round 8: Knit.
- Round 9: *K7, k2tog; repeat from * 8 times. 64 sts.
- Round 10: Knit.
- Round 11: *K6, k2tog; repeat from * 8 times. 56 sts.
- Round 12: Knit.
- Round 13: *K5, k2tog; repeat from * 8 times. 48 sts.
- Round 14: Knit.
- Round 15: *K4, k2tog; repeat from * 8 times. 40 sts.
- Round 16: Knit.
- Round 17: *K3, k2tog; repeat from * 8 times. 32 sts.
- Round 18: Knit.
- Round 19: *K2, k2tog; repeat from * 8 times. 24 sts.
- Round 20: Knit.
- Round 21: *K1, k2tog; repeat from * 8 times. 16 sts.
- Round 22: Knit.
- Round 23: *K2tog; repeat from * 8 times. 8 sts.
- Cut the yarn, leaving a 6″ tail. Thread it through the remaining 8 sts, pull tight.
About the Hat Cast-On Calculator
How many stitches to cast on for a hat comes down to three numbers: the head circumference, your gauge, and how much negative ease you want so the hat hugs instead of slipping. This calculator takes a Craft Yarn Council head size from preemie to adult XL (or your own measurement in inches or centimetres), a yarn weight with its typical gauge, and 10% negative ease by default. It rounds the count to fit a 1×1 or 2×2 rib or an 8-wedge crown, adds seam stitches if you knit flat, and gives the finished size, how long to knit before the crown, and a round-by-round decrease list.
How many stitches to cast on for a hat
Multiply your head circumference by 0.9 (10% negative ease), then by your stitches per inch, and round to your rib multiple. For an average 22″ adult head in worsted at 20 stitches per 4″ (5 per inch), that is 22 × 0.9 × 5 = 99, rounded to 100 stitches for a 2×2 rib. The same head needs about 108 stitches in DK and 68 in bulky.
Head size chart
The ranges below are the Craft Yarn Council head circumference chart. The calculator uses the middle of each range, adds newborn and baby splits the chart skips over, and adds an adult XL. Total hat height is the unfolded crown-to-brim length from the chart most pattern designers use; the XL height is our extension of it.
| Size | CYC head range | Calculator uses | Total hat height |
|---|---|---|---|
| Preemie | 9–12″ (23–30.5 cm) | 11″ | 4″ |
| Newborn (0–3 mo) | between preemie and baby | 14″ | 5″ |
| Baby (3–6 mo) | 14–16″ (35.5–40.5 cm) | 15″ | 5.5″ |
| Baby (6–12 mo) | 14–16″ (35.5–40.5 cm) | 16.5″ | 6.5″ |
| Toddler | 16–18″ (40.5–46 cm) | 17″ | 7″ |
| Child | 18–20″ (45.5–51 cm) | 19″ | 7.5″ |
| Tween / teen | 20–22″ (51–56 cm) | 21″ | 8″ |
| Adult woman | 21–23″ (53–58.5 cm) | 22″ | 8.5″ |
| Adult man | 22–24″ (56–61 cm) | 23″ | 9″ |
| Adult XL | above 24″ | 24.5″ | 9.5″ |
Measure around the widest part of the head, just above the ears and across the forehead, whenever you can. A real measurement beats any chart.
Cast-on stitches by size and yarn weight
These counts use 10% negative ease and a 2×2 rib (multiple of 4), knitted in the round. Gauge is stitches per 4″ in stockinette. For a hat knitted flat, add 2.
| Size (head) | Fingering 28 | Sport 24 | DK 22 | Worsted 20 | Aran 18 | Bulky 14 | Super bulky 10 |
|---|---|---|---|---|---|---|---|
| Preemie (11″) | 68 | 60 | 56 | 48 | 44 | 36 | 24 |
| Newborn (14″) | 88 | 76 | 68 | 64 | 56 | 44 | 32 |
| Baby 3–6 mo (15″) | 96 | 80 | 76 | 68 | 60 | 48 | 32 |
| Baby 6–12 mo (16.5″) | 104 | 88 | 80 | 76 | 68 | 52 | 36 |
| Toddler (17″) | 108 | 92 | 84 | 76 | 68 | 52 | 40 |
| Child (19″) | 120 | 104 | 96 | 84 | 76 | 60 | 44 |
| Tween / teen (21″) | 132 | 112 | 104 | 96 | 84 | 68 | 48 |
| Adult woman (22″) | 140 | 120 | 108 | 100 | 88 | 68 | 48 |
| Adult man (23″) | 144 | 124 | 112 | 104 | 92 | 72 | 52 |
| Adult XL (24.5″) | 156 | 132 | 120 | 112 | 100 | 76 | 56 |
Yarn labels give a gauge range, not one number. If your swatch is 18 stitches per 4″ in worsted, use the aran column or type 18 into the calculator.
Worked example: adult beanie in worsted
- Head: 22″. Gauge: 20 stitches and 28 rounds per 4″, so 5 stitches and 7 rounds per inch.
- Finished size at 10% negative ease: 22 × 0.9 = 19.8″.
- Raw stitches: 19.8 × 5 = 99. Nearest multiple of 4 for 2×2 rib: 100. The hat measures 20″ unstretched, which is 9.1% ease.
- Crown: 100 is not a multiple of 8, so a set-up round of *k23, k2tog* four times takes it to 96. Then 11 decrease rounds, every other round, take it to 8 stitches: 23 rounds in all, or about 3.3″.
- Knit to about 5.2″ from the cast-on edge, then start the crown, for a total height of 8.5″.
Plenty of worsted patterns cast on 88 for an adult. That works out to 20% negative ease on a 22″ head, which is fine for a stretchy 2×2 rib all the way up but tight in stockinette. Set the ease to 20% and you will get the same 88.
How negative ease works
Negative ease means the hat is smaller than the head, so the fabric stretches a little and grips. With zero ease a knitted hat slides down over the eyes by lunchtime. Around 10% suits most hats. Go toward 5% for thick bulky fabric or colorwork, which barely stretches, and toward 15% or more for ribbed hats and very stretchy wool. Slouchy hats still want ease at the brim; get the slouch from extra height, not width.
Crown decreases explained
The calculator splits the crown into 8 equal wedges. On each decrease round you knit to the last 2 stitches of every wedge and knit them together, losing 8 stitches. Knit one plain round between decrease rounds so the top stays rounded rather than pointed, and stop when 8 stitches remain. Then cut the yarn and pull it through the live stitches.
The crown takes up height. For a 96-stitch crown in worsted it is about 3″, so the calculator subtracts that from the total height to tell you when to start decreasing. If your row gauge differs, enter it for a more accurate figure. For a flatter top, switch to decreasing every round for the last 3 or 4 decrease rounds and knit a little longer before the crown.
How to use the Hat Cast-On Calculator
- 01Pick a head size from preemie to adult XL, or choose Custom and type a measured head circumference in inches or centimetres.
- 02Choose the yarn weight to load a typical gauge, then overwrite the stitches and rounds per 4″ with your own swatch if you have one.
- 03Keep negative ease at 10% (5–15% is the usual range), choose a 1×1 rib, 2×2 rib or plain brim, and pick in the round or flat.
- 04Read the cast-on count, finished circumference and how far to knit before the crown, then follow the round-by-round crown decrease list.
Frequently asked questions
How many stitches do I cast on for an adult hat in worsted yarn?
At 20 stitches per 4″ with 10% negative ease, cast on 100 stitches for a 22″ average adult head, or 104 for a 23″ head. The 100-stitch hat measures 20″ around before stretching. If you like a snugger ribbed beanie, 20% ease gives 88 stitches.
How many stitches to cast on for a hat in DK?
At a typical DK gauge of 22 stitches per 4″ and 10% negative ease, cast on 108 stitches for a 22″ adult head, 112 for a 23″ head, 84 for a toddler (17″) and 76 for a 3–6 month baby (15″), all at a 2×2 rib multiple of 4.
How many stitches to cast on for a hat with bulky yarn?
At 14 stitches per 4″, cast on 68 stitches for a 22″ adult head and 72 for a 23″ head. With super bulky at 10 stitches per 4″ it drops to 48 and 52. Chunky hats need fewer stitches, so a single stitch changes the size more; swatch first.
How many stitches to cast on for a baby hat?
In worsted at 20 stitches per 4″ with 10% ease: 48 for a preemie (11″ head), 64 for a newborn (14″), 68 for 3–6 months (15″) and 76 for 6–12 months (16.5″). Knit a total height of about 4″, 5″, 5.5″ and 6.5″.
How many stitches to cast on for a hat knitted flat?
Take the in-the-round count and add 2 edge stitches, one each side, that get used up in the seam. A 100-stitch worsted adult hat becomes 102 stitches cast on flat, and it still finishes 20″ around once seamed.
Should the cast-on be a multiple of 8?
Only if you want the crown to split into 8 wedges with no adjustment. A 2×2 rib needs a multiple of 4 and 1×1 a multiple of 2; if the count is not a multiple of 8, work one set-up round that decreases 2, 4 or 6 stitches evenly, then start the 8-wedge crown.