Knitting Compensation

I am making a hat, the pattern calls for size 8 needles and worsted yarn. I want to use a yarn that is medium (4). If I use size 10 needles, in order to see that I have the right gauge, I have to knit a swatch right? The gauge says 17 stitches x 23 rows = 4 inches in stockinette, does that mean that there are about 4 stitches an inch? This is so confusing to me!

Yup, you gotta swatch. Actually it’s more like 4.25 stitches per inch, you need to make your swatch more than 4" wide and about 4" long to get an accurate count. You also need to get it off the needles, so bind off too.

So lets say I make the swatch 8 x8, do you think that’s a good size? I just cast on however many stitches I think I will need? I think that’s the hardest part, because I feel like the amount that I cast on, sometimes it doesn’t make sense the size it becomes, does that make any sense?

But lets say I cast on enough that it’s 8 inches, I make my swatch, then I measure, if it’s about 4 stitch an inch I am okay, if it’s less than that, i have to use smaller needles, in order to use the same yarn, if it’s more than that, I have to use bigger needles? I am just trying to wrap my head around this.

The only way to know your own gauge with a particular yarn and needle size is knit a gauge swatch. Start with the needle size suggested and if that doesn’t give you gauge then either go up or down a needle size and try again. You only need to make the gauge swatch about 4x4. Enough to measure the stitches in the center of it.

The gauge you listed would be 4.25 st per inch. That extra .25 can make a difference over a large amount of stitches. How important it is depends on the project and what stitch will be used.