Accomodate gauge & round # differences?

I’m trying to figure out what to do to accomodate differences in my gauge from the pattern’s gauge. The pattern calls for “8 stitches and 10 rounds = 1 inch.” The wool label says “24 sts x 30 rows = 4” x 4."
And in my test swatch, I got 6 stitches and 8 rounds = 1 inch. I used the correct size needles (4) specified for the pattern.

I know I can’t just go ahead and follow the pattern given my gauge swatch. My question is, can I simply decrease the number of stitches to cast on or do I have to go buy a different size of needle? I do have size 6 needles, but how do I know if size 6 would work? Or how to decide what new size of needle to buy to get accurate dimensions on the finished pattern?

Also, how to I accomodate for the differences in number of rounds?

Thanks!

It really depends on what you’re making. If you’re making a scarf, for example, you can change the number of stitches you cast on. If you’re making a sweater, that would be difficult to do and still be sure you end up with a sweater that fits.

In order to get your gauge to 8st per inch, you’ll have to go down in needle size. Thinner needles would give you more st per inch. It’s hard to say if you’ll need to go one or even two sizes smaller.

Another option, which I’ve done, but can’t give a formula on, is if its a garment, is to make a smaller size than you normally would, but this is risky.

Your stitch gauge is the most important to get here. The number of rounds can be adjusted as you go, but you can’t change the width.