You can make a top-down hat out of any weight yarn and any size hook or needles – no pattern necessary! I use a simple βrecipeβ when knitting or crocheting a hat, and it works beautifully every time.
A word about circumference.
This is where your high school geometry class comes in handy.
There are a lot of charts regarding average circumference sizes for various sizes of hats. I will show you my general guidelines. However, circumference isn’t the easiest measurement to use when knitting. For me, I typically have one of my small needle gauge / rulers handy, and they are about 5 inches long. So, I measure the radius of the hat.

The radius of a circle is the length of a line drawn from the center of a circle to the edge. The radius is 1/2 the diameter. Diameter is the length of a straight line, passing through the middle of a circle, from one edge to the other. To calculate our desired radius, using the desired circumference, we use the formula π = πΆ / 2π or π = πΆ / 6.283, where r=radius and C=circumference.

So, if we want an adult hat with a circumference of 23″, we divide 23 by 6.283 to get a radius of 3.66″. Use this technique for whatever circumference you would like to achieve, and stop your increases when you get to the desired radius.
It’s a lot less complicated than it sounds. Once you make your first hat, you’ll get the idea.
Size Chart
This chart is a modified version from KnitPicks.
Age | Radius | Head Circumference | Hat Height | Yardage |
Preemie (1-2 lbs) | 1.43″ | 9β³ | 3.5β³ | 50-110 |
Preemie (3-4 lbs) | 1.75″ | 11β³ | 4β³ | 50-110 |
Preemie (4-5 lbs) | 1.9″ | 12β³ | 4.5β³ | 50-110 |
Preemie (5.5-6 lbs) | 2.07″ | 13β³ | 5β³ | 50-110 |
Newborn | 2.23″ | 14β³ | 6β³ | 100-150 |
Baby β 3 to 6 months | 2.71″ | 17β³ | 7β³ | 100-150 |
Baby 6 to 12 months | 2.86″ | 18β³ | 7.5β³ | 100-150 |
Toddler β preschooler (12 months β 3 years) | 3.02″ | 19β³ | 8β³ | 100-150 |
Child (3 β 10 years) | 3.18″ | 20β³ | 8.5β³ | 100-180 |
Pre-teens and Teens | 3.34″ | 21β³ | 10β³ | 100-180 |
Adult Woman | 3.58″ | 22.5β³ | 11β³ | 120-200 |
Adult Man | 3.58″ – 3.82″ | 22.5β³-24β³ | 11.5β³ | 200-255 |
Knit
Terms to know: k1 = knit 1, kfb = knit front and back, p1 = purl 1
Cast on 8 stitches using circular or double pointed needles for knitting in the round. Place marker at end of round, if desired.

Round 1: Join in the round and knit one round.
Round 2: *kfb* repeat to end of round (16 stitches total).
Round 3: Knit
Round 4: * k1, kfb * repeat until end of round (24 stitches total).
Round 5: Knit
Round 6: * k2, kfb * repeat until end of round (32 stitches total).
Round 7: Knit
Round 8: * k3, kfb * repeat until end of round (40 stitches total).
Round 9: Knit
Round 10: * k4, kfb * repeat until end of round (48 stitches total).
Repeat in this fashion, increasing one knit stitch in each of the 8 knit sections every even round until the desired circumference is reached.

If you have to put down your hat and don’t remember where you were, count the total stitches, divide by 2 (or just count 1/2 if you are on circulars), subtract 4 and then divide the remainder by 4. This will tell you how many knit stitches to make before your kfb.
Continue to knit in the round until you’d like to start your ribbing. Use any method you’d like that is divisible by 4. I usually use k2, p2 ribbing, but you can also use k1, p1 or k4, p4, or a basket weave stitch, or garter stitch, etc.
Once you have reached your desired length, bind off using your favorite method. I use Grandma’s Favorite Bind-Off, but have apparently been doing it wrong, because I have been purling two together. Whoops.
Break yarn and secure. Weave in ends and you are done! Enjoy your new hat!
Crochet

Crocheting a top-down hat begins with making a flat circle to your desired circumference. Remember that you can use the radius and stop increases when you get to your desired size.
Terms to know: sc = single crochet, 2 sc = 2 single crochet in the same stitch
Chain 6, join with a slip stitch to form a circle.
Round 1: Single crochet 8 inside the circle.
Round 2: 2 sc in each stitch around (16 stitches). Join with slip stitch. chain 1.
Round 3: sc in each stitch around. Join with slip stitch. chain 1.
Round 4: * sc, 2 sc * repeat until end of round (24 stitches). Join with slip stitch. chain 1.
Round 5: sc in each stitch around. Join with slip stitch. chain 1.
Round 6: * sc, sc, 2 sc * repeat until end of round (32 stitches). Join with slip stitch. chain 1.
Round 7: sc in each stitch around. Join with slip stitch. chain 1.
Round 8: * sc, sc, sc, 2 sc * repeat until end of round (40 stitches). Join with slip stitch. chain 1.
Round 9: sc in each stitch around. Join with slip stitch. chain 1.

Repeat in this fashion, increasing one sc in each of the 8 sections every even round until the desired circumference is reached.
Once you reach your desired circumference, continue to sc around, but now you can stop joining the ends of the rounds and just crochet in a swirl until the desired length is reached.
Break yarn, secure, and weave in ends. You’re done!