How much yarn will I get out of 4 ounces of roving? I know it will depend on the weight of the yarn, but is there a generic formula to figure it out?

Check out your favorite brand of wool yarn. Most skeins are 50 gm or 1.75 oz. How many yards in your favorite weight of yarn?

Cascade 220 is 100gm or 3.5 oz and is 220 yds. Once you spin the 4 oz, you may have a bit of waste, but not much.

Does this sort of help?

It does…thank you!