How much does Patons Merino shrink?

I am making a hat for my hubby with no pattern since I couldnt find one that would be felted. Has anybody found one before?
How much does Patons Merino shrink when felted? :??

You’ll have to knit up a swatch and felt it to find out.

knit up a 6x6" inch swatch in your patons merino, then mark out a 4x4" square in the center an acrylic yarn. felt the swatch and then measure that 4x4" square. then you’ll know how much it felts.