There’s rough consensus around these birth year cutoffs for the four most recent American generations:
Baby Boomers: 1946-1964
Of course, any birth year cutoff is arbitrary. (I’ve written more about that HERE and HERE). For example, maybe Millennials begin in 1979 or 1982 instead. That’s certainly possible – there is no bright dividing line between GenX’ers and Millennials. There are more definite breaks in the data between those born in the early 1990s and the mid-1990s, probably due to the smartphone, so the 1995 cutoff has some data to back it up. It’s too early to know what the end date will be – 2012 is just a rough guess.
It’s also inherently problematic to group people in 20-year blocks – someone born in 1980 had a different cultural experience from someone born in 1994. And if you were born in 1979 vs. 1980, are you really a different generation? In most studies, we’ve looked at birth year continuously, instead of grouping people into generations.