you can find hat to head part 1 here.

the first part of the basic hat is essentially a tube composed of some sort of brim treatment and then the body of the hat. the question that most people have at this point is how far to knit before starting to decrease. the first thing you need to know to figure this out is the overall height goal for your hat.

approximate hat heights

0-6 mo. – 5 in. (12.7 cm)
6-18 mo. – 6.25 in. (15.9 cm)
18 mo.-4 yr. – 7.25 in. (18.4 cm)
4 yr.-adult s – 8.25 in. (21 cm)
adult m-l – 9 in. (22.9 cm)

the maths

truthfully, i never do the maths. most decreases i do take between 2-3 in. (5.1-7.6 cm) to complete. and if i need it to come in faster, i can change it like i did below on row 21. but here’s how you figure it out.

total number of sts / the number of sections i want to decrease over = number of sts in each section
in this instance, i will use 96 / 6 = 16
but there’s also 96 / 16 = 6
or 96 / 8 = 12
or 96 / 12 = 8 – so many possibilities!!

but i digress – the math for my hat means my set up row or first round of decreases will be
row 1: k14, k2tog – 90 sts (repeat around)

because k14 plus the 2 in the k2tog is 16 and 16 sts is the size of one of my decrease sections. during the first round, you can also place a marker on the needle after each k2tog and then decrease the 2 stitches before each marker every other row.

row 2: and all even rows – knit plain
row 3: k13, k2tog – 84
row 5: k12, k2tog – 78
row 7: k11, k2tog – 72
row 9: k10, k2tog – 66
row 11: k9, k2tog – 60
row 13: k8, k2tog – 54
row 15: k7, k2tog – 48
row 17: k6, k2tog – 42
row 19: k5, k2tog – 36
now i start picking up the pace because i’d like the hat round rather than slightly pointy.
row 21: *k1, k2tog* – 12
note the even number – row 22: k2tog – 6

most basic hats have one knit row between each decrease row.  hats can vary greatly in the decrease section, from slowly coming in for a smooth top to dramatically coming in for a more lumpy or flat top. i’m doing a gradual decrease on this one, as seen above. so let us see how tall my tube will be when i need to start decreasing.

we know from the rows written out above that i’m decreasing over 22 rows
my row gauge is 7.5 rows/in. (2.5 cm)
total number of rows decreased over / rows/in. (2.5 cm) = number of inches (cm) it will take to decrease
22 / 7.5 = 2.93 in. (7.4 cm)

i will need about 3 in. (7.6 cm) to finish.

gratuitous try the hat on your head while still on the needles picture

do this! now that you know your goals for circumference and height, measure across the hat and make sure it is the size you want after you get a few inches in. try it on your head.  double check your gauge.  in the same way that you might compare a sweater you’re making to one you own to make sure you’re on the right track, check out your hat while knitting.  you have control over sizing and fit.  you do!

i’m off to start decreasing.

next up, the finished hat!  and the tam/beret and the search for the perfect brim.