Sport is considered a 2, dk a 3, worsted a 4. I think it depends so much on the actual yarn that you do need to approximate and then knit with it and measure your gauge, like cheesiemom recommended.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry