Yarn Gague question

[paiva]

HI EVERYONE....quick question.
I have a project that calls for the following gague:
12 St/16 rows = 4” in St st. on size #11 US needles
Beacuase I am mathematically challenged and can't figure this one out myself I would like to ask if I could use yarn with the following gague for it:
3 st/" - 9 rw/2" on size 10.5 US
If I have to change the needle size to make it work for this yarn, would I just knit it on 10.5's?

[Plantgoddess+]

The yarn you want to use is 6 stitches to 4" on 10.5 needles which is considerably different than 12 stitches to 4" on the project gauge. I would do a swatch and see how close you come to gauge for the project and see if you can go down a size or 2 on needle size without changing the texture and drape of the project too much for comfort. Otherwise I would look for a different project or different yarn.

[suzeeq]

You might consider making a different size; figure out how many sts/inch you get on size 11s and see if a different size will have close to the stitches you'd need to fit.