Changing yarn and needle size for pattern

I have a pattern for a women’s sweater I want to make but it is done in bulky yarn and size 11 needles. What size needles would I need to use if I changed the yarn to knitting worsted (4 ply) without changing the size of the sweater?
Thank you.

For a worsted eight yarn, you could use needles in the size 7-9 range depending on how tightly or loosely you knit. Make a good sized swatch with your yarn and determine how many sts you get per inch. That way you can decide which sweater pattern size will give you fit that you want.

You could use a size 8 or 9 and work a larger size of the pattern. Figure out your sts per inch and divide that into the sts given at the bust area and use the size that’s closest. If it’s a top down raglan, you can cast on for a larger size and increase until the back sts measure about half what you want at the bust, then just follow the rest of the pattern.