Seems to me it’s pretty straightforward and is 12 months.
if you had a prior membership (which for example expired on 12/31), you get another year added with the same expiration day.
if you didn’t, you get 12 months from when you select it.
has anyone seen anything to the contrary? I don’t think anyone got 20 months based on the replies above. People just got +12 to an existing membership that still had 8 months left, no?