Pattern/yarn changing question

I have a question. I have a pattern that calls for a certain yarn. I have another yarn that I want to use for the pattern. The yarn I want to use is slightly ‘thicker’ than the pattern yarn. How do I go about adjusting for this? Thanks!

tricia.

your best option IMHO would be to do a guage swatch, then compare the stitches per inch in that to the stated guage in the pattern then do your tweaking from there.