Cast on and join your stitches to start the crown
To knit a hat on circular needles, you cast on stitches the same way you would for any project, then join them into a ring so you can knit in continuous rounds instead of back and forth. Most adult hats need between 80 and 120 cast-on stitches, depending on head size and yarn weight—a worsted-weight yarn for an average adult head typically uses around 100 stitches on US 6 or 7 needles.
Cast on your stitches using the long-tail method or your preferred cast-on technique. Lay the circular needle flat on your work surface and count your stitches to make sure you have the right number. The most common mistake here is twisting the stitches as you join them into a ring—if your cast-on row spirals around the needle instead of lying flat, your hat will have a twisted edge that you cannot fix later.
To join without twisting, hold the needle so the working yarn hangs from the right needle tip. Slip the left needle tip through the first cast-on stitch, then knit that stitch with the working yarn. You have now joined your stitches into a circle. Place a stitch marker on the right needle after this first stitch so you know where each round begins and ends.
Key Takeaways
- Cast on 80 to 120 stitches depending on head size and yarn weight, then join them into a ring without twisting the cast-on row.
- Knit in stockinette stitch (knit every stitch every round) for the body of the hat, which takes about 6 to 7 inches for an adult.
- Decrease stitches evenly around the crown by knitting two stitches together at regular intervals until you have 8 to 12 stitches left.
- Cut the yarn, thread it through the remaining stitches, and pull tight to close the top of the hat.
- Weave in the yarn ends and block the hat gently if needed to even out the stitches.
Knit the body in stockinette stitch for 6 to 7 inches
Once you have joined your stitches, knit every stitch in every round. This creates stockinette stitch, the smooth V-pattern that most hats use. Keep knitting in rounds until the hat measures about 6 to 7 inches from the cast-on edge for an adult—measure by laying the hat flat and checking the distance from the bottom to where your needles are. If you are making a hat for a child, aim for 4 to 5 inches instead.
As you work, you will notice the hat takes shape around the circular needle. The needle should feel full but not cramped—if your stitches are bunched tightly, you may have cast on too many. If there is a lot of slack, you cast on too few. Either way, the hat will still work, but the fit will be off.
Watch for laddering, which happens when the stitches at the stitch marker look loose or uneven. This is common when you switch from one needle to the other. To prevent it, pull the working yarn snug as you knit the first stitch after the marker. Some knitters also tighten the last stitch before the marker. Both techniques help the transition look smooth.
Decrease stitches evenly to shape the crown
When the body reaches the right length, you begin decreasing to close the top of the hat. The most common method is to knit two stitches together (a decrease called K2tog) at regular intervals around the crown. Space your decreases evenly so the hat closes in a point rather than bunching to one side.
To space decreases evenly, divide your total stitch count by the number of decreases you want to make. For a hat with 100 stitches, if you want 10 decreases in one round, you would decrease every 10 stitches. Knit 8 stitches, then knit the next 2 together, and repeat around the entire round. After this round, you will have 90 stitches.
Continue knitting plain rounds between decrease rounds. Most hats use one plain round between each decrease round, though some patterns use two. Keep decreasing every 10 stitches (or whatever spacing you chose) in every other round until you have 8 to 12 stitches left on the needle. At this point, the opening is too small to knit comfortably, and you are ready to close the top.
Close the top by threading yarn through remaining stitches
Cut the working yarn, leaving a tail about 6 inches long. Thread this tail onto a yarn needle (a blunt needle with a large eye). Slip all remaining stitches off the circular needle and onto the yarn needle. Pull the yarn tail snug so the stitches gather and close the hole at the top of the hat.
Pull the yarn tail to the inside of the hat and weave it through the gathered stitches a second time for extra security. Then weave the tail down through several stitches on the inside of the hat to anchor it. Trim any excess yarn.
Weave in the cast-on tail and block if needed
Go back to the cast-on edge and locate the yarn tail you left when you cast on. Thread this tail onto the yarn needle and weave it through the cast-on stitches on the inside of the hat, moving up and down through the loops. Weave for at least 2 inches, then trim the excess.
At this point, your hat is finished and wearable. If the stitches look uneven or the edges curl, you can block the hat by wetting it gently, squeezing out excess water, and laying it flat or on a hat form to dry. Blocking is optional and works best with natural fibers like wool or cotton. Synthetic yarns do not hold a blocked shape as well.
Common mistakes and how to fix them
The most common problem is a hat that is too tight or too loose around the head. This usually comes from casting on the wrong number of stitches or using the wrong needle size for your yarn. If your finished hat is too small, you can sometimes stretch it gently while it is damp and let it dry in the larger shape. If it is too large, there is no straightforward fix—you would need to unravel and reknit with fewer stitches.
Another frequent issue is a visible seam or jog where the rounds meet at the stitch marker. This is normal and becomes less noticeable with wear and washing. Some knitters hide it by moving the stitch marker one stitch to the right every few rounds, which spreads the jog around the hat instead of keeping it in one place.
If you drop a stitch while knitting, stop when ready and pick it up with a crochet hook before it runs down several rows. Insert the hook through the dropped stitch from front to back, catch the horizontal strand of yarn above it, and pull the strand through the stitch. Repeat for each row the stitch dropped.
Frequently Asked Questions
What size circular needles do I need for a hat?
Use the needle size recommended on your yarn label. Most worsted-weight yarns call for US 6 to 8 needles. The needle length should be 16 inches for an adult hat—this is short enough that the stitches do not spread out too much. Some knitters prefer 24-inch needles or use the magic loop method with longer needles, but 16 inches is the standard.
Can I knit a hat on straight needles instead of circular needles?
Yes, but you will knit flat instead of in rounds. Cast on, knit to the end of the row, turn, and purl back. This creates a seam down the back of the hat that you sew together at the end. Most knitters prefer circular needles because there is no seam and the hat is faster to finish.
How do I know what size hat to make?
Measure the head you are knitting for around the fullest part, just above the ears. An adult head is typically 21 to 23 inches around. A child's head is usually 16 to 20 inches. Subtract about 1 to 2 inches from this measurement—hats should fit snugly but not tight. If the head is 22 inches, cast on stitches that will give you a finished hat of about 20 to 21 inches.
What if I run out of yarn before the hat is finished?
You can join a new ball of yarn at the beginning of a round by tying the old yarn to the new yarn with a square knot, or by overlapping the ends and weaving them in later. Tie the knot on the inside of the hat where it will not show. If you are close to the crown, you can also stop early and close the top with fewer stitches, which makes the hat slightly smaller.
Do I need to block a hat after I finish it?
Blocking is optional. It evens out uneven stitches and can help the hat hold its shape, but it is not required. If you want to block, wet the hat, squeeze out water gently, and lay it flat or on a hat form to dry. This works best with wool and cotton. Acrylic yarn does not hold a blocked shape as well.