Skip to main

Generational Birth Years

Where do the generations begin and end? Here's what CGK's research has uncovered.

We are frequently asked why generations are different lengths as well as why the birth years for generations vary from different sources. As a research firm, we take generations seriously. To us, generations are not cute stories or catchy memes but groupings of people who help us to see them and the world differently—and more clearly.


At The Center for Generational Kinetics, we believe generations are not boxes but powerful, predictive clues on where to start to faster connect with and influence people of different ages and life stages. This is true for uncovering hidden insights into sales, marketing, employment, voting, spending, marriage, and much more. Based on our numerous research studies, we use the birth years listed below as the general beginning and ending years for each of the five generations:

  • Gen Z, born 1996 to 2015
  • Millennials, born 1977 to 1995
  • Gen X, born 1965 to 1976
  • Baby Boomers, born 1946 to 1964
  • Traditionalists, born 1945 and earlier

It’s really important to note that you can be born within three years on either side of the beginning or ending of a generation and have all the characteristics of the generation before or after. This has to do with a number of factors including the age of your parents, if you grew up in an urban or rural environment, affluence, education and more. Being raised in a military household can also change your generational identity.

For Millennials (aka Gen Y) in particular, we use the birth years 1977 to 1995 for North America.

This birth range is slightly different than some other sources that believe the ending cutoff for Millennials is 2000. We strongly believe that the 2000 birth year is incorrect. The reason: the most important, generation-defining moment for Millennials (particularly in the U.S.), was September 11, 2001. It’s extremely difficult, if not impossible, to be born between 1996 and 2000 and have a strong, emotional connection to 9/11. Your brain is simply too young to put the event in a cultural, geographic, or other context. From our research-based vantage point, if you were born in the U.S. and 9/11 has always been history to you—something you literally cannot remember—then you are not a Millennial but a member of Generation Z.

You can watch CGK President Jason Dorsey deliver a presentation on Gen Z, Millennials, and the generations here.

In terms of the starting years for Millennials, a similar approach applies but without a clear, defining moment to identify the beginning of the generation. In this case, we look for patterns or consistency in behaviors and viewpoints in our national and international research studies. For this reason, we use 1977 as the beginning birth year for Millennials. We know that other groups use 1980, but from our vantage point, the consistency in shifting from Gen X to Millennial starts around 1977, not 1980.

For the purposes of understanding and bridging generations, you could use either year as the starting point for the generation. It’s less important to focus on a single year and more important to focus on the underlying consistency, or lack thereof, when it comes to behaviors. In most cases, except for generation-defining events like 9/11, the transition from one generation to the next is more gradual and blended over a few years.

Using the birth years 1977 to 1995 to define Millennials, there are about 83.5 million members of this generation in the U.S. This makes them the largest generation of employees in the workforce and the largest generation of consumers.

To learn each generation’s characteristics, click here

Blog Category

Recent posts