Pattern issue

I’m using a pattern from an Internet site based in the UK. I went to a local yarn store and they told me that Heartland yarn (Lion Brand) was equivalent to the Aran weight yarn called for in the pattern. However, when I cast on 18 stitches on #6 (equivalent to 4mm needles called for in the pattern) needles, it didn’t measure 4 inches, which it was supposed to. I tried #8 needles, but still didn’t get 4 inches. I think the yarn weight is probably incorrect, but I really don’t know because this is a very knowledgeable yarn store. Thanks in advance for your help.

Welcome to KH!
The Lion Brand Heartland is classified as Aran (16sts/4 inches).
When you do a gauge swatch, cast on more than the number called for in the pattern tension. This is because the end sts won’t have the width of more central sts. Cast on about 24sts and knit for about 4 inches. Then measure the number of sts across the center 4 inches to find out your gauge.

Which pattern are you making?

I realized I wasn’t knitting a swatch (the instructions are unclear), so when I did, it came out okay. Thanks for your help!:aww:

I’m making Denim Blue Baby Cardigan