Does this gauge seem right?

I don’t know if I did this right. It’s my first time trying to make a hat. I’m using size US 17 circular needles and I knitted a swatch and I don’t know if I determined the gauge right. I turned out to have 2 knits per inch. (I’m using a heavy wieght yarn) and my head measurement was 18.5 inches, so that’s only 37 inches? Maybe I didn’t measure the stitches right? I just put a ruler up to the stitches and measured how many were in an inch. Here a question though, when measuring the stitches per inch, I just measured the stiches that were facing down? Does that make sense, and is that right?
I’m just really confused and I don’t want my hat coming out too small.

I knitted a swatch of 20 stitches for 4 inches and the 20 stitches aren’t enough to get around half of my head, so how will only 37 be enough? I really think I did it wrong.

I’m assuming you want a lacy hat since you’re using such large needles with your yarn? You said heavyweight, but what does the tag say? Does it have a number on it? Does it have a gauge or suggested needle size?

I looked up hats made with those size needles to see what the cast on was.

This one is 37 st, but the yarn used is super bulky.

This one is 72 st, and they used super bulky yarn, but a size 10 needle.

Here’s some info about measuring gauge.

Just try casting on for the hat, use 36 sts. The cast on is smaller than the knitted item will be, so hopefully you worked for about 3". Make sure your cast on isn’t too tight, hats do stretch a lot so if you’re getting 2 sts per inch then that’s about right.

Alright, thank you everyone! I’m still new to the site, but I appreciate the help! and we’ll see what happens with the hat!

The number of stitches per inch sounds about right. Your cast on and first row are always going to be a little tighter than the rest of the work. It relaxes as you knit more rows. This is why it’s important to measure your gauge after you’ve knit an inch or more. In order for this to fit over your head, you need to either cast on loosely or use a twisted German cast on. I use the German cast on for hats, mittens, gloves, and socks. It stretches and allows you to get these on easier. It’s especially helpful for children’s items, as they’re in a hurry to dress, or for mothers having difficulty dressing a fussy child to go outside.