One fellow who got spread around an awful lot stated that it was "anyone born between the years of 2000 and 1986".
Wait, why do you emphasise the 86? That's the one that's actually in the right range; it's the 2000 that's way off. Millennials are supposed to be people who were reaching young adulthood on the cusp of the millennium.
If Milennial is a generation of the same scale as the other generations then it should span
at least 15 years if not 20 years. I've noticed some Milennials
want to define their own generation as a very narrow one, which - i strongly suspect - is centred on their own personal birthday, because the argument is usually that they "can't relate" with people born more than 5 years on either side of their own birth year. Which is an extremely self-centred way to define a "generation" since you'd therefore be lumping in people +5 years older with people -5 years younger, e.g. 10 years apart because of the personal "i can't related to people more than 5 years older/younger than me as being in my 'generation' "
Nope, just stick it at 20 years, or 15
being generous - since we're already lumping in Baby Boomers and Generation X as being 20 years long each. One possible fix for the mentioned issue is to shrink Gen X to 15 years, 1965-1980, then say Millennials are 1981-1995. Gen Z would then be 1996-2010.
EDIT: if you want the "cusp of the millennium" definition to work, then you need the center of the cohort turning 18 in 2000, so you want 1982 +/- 7 years. This would give you Boomers: 1946-1960, Gen X, 1961-1975, Millennials 1976-1990, Gen Z: 1991- 2005. This is a
neat definition, but it's non-standard compared to how people actually use the terminology. However, a more standard interpretation would be the "first generation who came of age after the millennium", which the 1986-2000 cohort matches.