I typically wear a woman’s XL toXXL top, size large unisex shirt for a standard fit.
I ordered an XL and it fit like a standard large sweatshirt. If you would like an oversized fit, I would size up one.
That being said, this fabric is INCREDIBLY. I have never felt a sweatshirt like it. It is about the same thickness as a typical sweatshirt, but the material is much different. It is incredibly soft.