Changing gauge

Hello there. I have a question about changing the gauge of something. I’m planning on knitting a sweater for my sister (surprise gift) and I found a pattern I like. However, I think the smallest size may still be too big for her (she’s petite and thin). Could I make the same pattern but change the gauge so that there will be more sts per inch to make it smaller? And how can I tell whether this new gauge is appropriate/will be her size? Thanks!

If you use a smaller needle and the same yarn weight, it may be a little stiff, so you’d need to use a thinner yarn too. Knit up a sample to see how many sts per inch you get (CO at least 24 sts) and divide the sts/inch into the number given for the small size back and front stitches. See if that will give you the measurement you need.

Thanks. I knitted up a small sample yesterday…am at about 6.5 sts/inch in a k3, p3 rib pattern, without stretching or ironing. Their gauge is 23 sts and 36 rows to a 4" ribbed pattern, stretched and steam ironed. How do I know how far to stretch (in order to see about the gauge)?

I guess stretch it how far you think it’ll be stretched while wearing. Not as far as it can got, but not unstretched.