60k if single, 100k if married; up to
300k if single, 500k if married
but class isn't just about income. most secondary school teachers here make less than 60k and i would consider teachers by definition middle class.
i think it's more like if you get paid hourly, you're working class. if you get a salary, you're middle class. if your primary source of income is property/investment, that's upper class. small business owners are probably their own class entirely, since they make money off profit but it might not be that much.