Originally Posted by knittingmom27
That's probably why I have made things where "size" didn't really matter as long as it looked nice and even by eye.
That to me is a perfectly acceptable way of determining your gauge and needle size for the pattern you are developing. :D
In general, smaller yarns are knit with smaller needles and larger yarns with bigger. Most yarn lables will give you a suggested needle size and approximate gague. That being said, you can use a range of needle sizes for a given yarn depending on how you want it to look. For example, I will knit worsted weight yarn with needle sizes 3-8 depending on how dense I want the finished fabric (smaller needle=denser). Similarly, I use size 8 to make hats out of a bulky yarn, but have used the same yarn with size 11 and even 13 (!) needles for scarves and shawls because I wanted them more open and flexible.
Getting back to your question on determining the gague for your bag, I suggest working some test swatches (about 5 inches square) on a few needle sizes using the stitch pattern for your bag. Maybe start with size 8 (or what is recommended on your yarn label) and adjust up or down by a size or two depending on how it looks. Once you have one that you like the look of, measure off four inches and count the number of stitches in it. This is your gauge. (see Amy's gauge tips here
- 5th post down) Now calculate out from this the number of stitches you need to cast on for your desired width.
Good luck and happy knitting! :XX: