Gauge question

I bought a new book of patterns and today just visited Tradewind Knitwear shop (Lucy Neatby) and bought some wool yarn. The instructions for the pattern called for worsted but they didn’t have the colour I wanted so I got something a bit thicker than dk. I knit a few rows of stockinette to measure the gauge and I’m way off. 16 sts cast on and 22 rows (in stockinetter) was supposed to give me 4 inches across (I think) but I only got about 3.5 inches. Would using bigger needles help or should I just abandon and get a different weight wool?

You could use bigger needles, but that may give you a knit that’s too loose. Another option is to knit a larger size. You really have to knit more than 16 sts for a gauge swatch, CO about 20-24 and measure 4" in the middle. The edge sts aren’t the same size and curl under. One you find your sts/ inch in a gauge that’s not too loose multiply the sts time the inches you need and see if there’s a pattern size that’s close to that number. If it’s a sweater, that would be sts for the front and back.

If it’s a scarf, btw, you can just follow the pattern, but it will be somewhat narrower than the pattern.

When I knit a gauge swatch, I always cast on 26 stitches; I knit 3 rows for a garter border, then keep the 6 edge stitches in garter stitch while knitting the center 20 stitches in stockinette… so on right side rows I knit across, and on wrong side rows I knit 3, purl 20, knit 3 .
Then, I measure just the stockinette portion, and divide 20 (the number of stitches) by the measurement.