I find this type of wool tends to be a little loftier (I.e.warmer), scratchier (felts easier so shrinkage prone). So if it's a question, I'd go up a size. I highly recommend hand washing in your bathtub or a bucket with minimal agitation using a soap like Euclan which contains some lanolin. I find the lanolin is deodorizing/antibacterial, softening, and the garment will last longer. Enjoy! I bought one second hand from Etsy and chose to use the hand wash settings on my machine to shrink a little as mine was very much a size too big. Now it's small enough I think I'll stick to hand washing going forward. (Press the extra water out, roll on a couple towels to squeeze out water, and lay flat to dry)