The finished square feet are tracked by the government, for tax purposes, and yes, they tax your bathroom and closet, even if it's shaped weird. Measuring and omitting those when selling your house would be a huge headache just for the purpose of ... screwing yourself out of potential buyers?
As a counter-example, for France anything under 5ft is not counted. Areas under the stairs, that edge area of slanted ceilings, areas above a loft can't be counted. You can include it but the official number is footspace that is standing height.
My realtor described it as everything under air meaning that if the space is heated or cooled, then it's counted. So the garage is out, but bathrooms and hallways and closets are in.
That's not exactly correct - part of my basement is heated/cooled but I'm pretty sure that doesn't count towards square footage (at least, the appraisal didn't count it).
Are you somewhere where people don't have basements?
Usually it's about finished vs. unfinished. I've never thought about whether my basement is heated or not. I mean it doesn't have radiators but that's where the furnace is and if the basement got too cold that would be problematic because of pipes. But it's very unfinished :-)
I don't think it's completely unreasonable, particularly in the case of bathrooms. Larger bathrooms (to a point) are nicer than smaller bathrooms, and that should be reflected in the square footage.
