[marnett]

Social class PSA:

Lower, middle, upper-middle, upper class, etc do not map (as much as news media tries) to income levels. Middle class does not identify a level of income.

To identify income levels use quintiles instead.

Middle class is a social class and annual income has no causal effect on social class.

[refurb]

Depends on the country. I know in the UK class is distinct from income. In the US it's very closely linked.

[marnett]

I think how the term is used is different, as you mention, in the US and UK. I'm trying to prevent Americans from assuming social class and income brackets are linked. Most Americans just assume, likely due to class brackets being used by the media as an economic indicator, that lower, middle, etc class just correlate with one's salary; this form of usage is a misnomer and ought not be used.