Generations by birth year: from the Greatest Generation to Gen Beta

Generation names are everywhere, from news headlines to workplace training and family arguments over the dinner table. Yet ask three people when the Millennials end and Gen Z begins and you may get three different answers. This guide sets out the birth-year ranges that are most widely used, explains who came up with them and why they vary, describes each generation briefly, and shows how many people were actually born into each one. It finishes with the honest part: what a generation label can tell you, and what it cannot.

The generations at a glance

The table below uses the ranges that have become the standard reference in the United States, largely because they are used by the Pew Research Center, a large non-partisan polling organisation, for the generations from the Silent Generation to Gen Z. For the youngest two, it follows the names proposed by the social researcher Mark McCrindle, with Generation Alpha starting where Pew’s Gen Z ends. Our generation calculator uses exactly the same ranges.

The ages in the table are the ages people in each generation turn during 2026, depending on whether their birthday has passed yet. A Millennial born in December 1996 is 29 for most of 2026 and turns 30 at the very end of it, while one born in January 1981 turns 45.

Who decides the dates?

No international body sets generation boundaries. In the United States the Census Bureau formally defines only one generation, the Baby Boomers, as people born from 1946 to 1964. That range is anchored in real data: births in the US rose sharply in 1946, after the Second World War, and stayed high until the early 1960s before dropping in the mid-1960s. Every other range was proposed by writers, researchers or marketers and then adopted by others, which is why they shift a little from source to source.

Some names came from books. “Generation X” was popularised by Douglas Coupland’s 1991 novel of the same name, and the authors William Strauss and Neil Howe coined “Millennials” in their book Generations, published the same year. Strauss and Howe originally dated Millennials from 1982 to 2004, much later than most sources use today. In 2019 Pew announced that it would treat 1996 as the last Millennial birth year and 1997 as the first year of Gen Z, reasoning that the oldest Millennials had come of age around the turn of the century and the 9/11 attacks, while those born from 1997 had little or no memory of them and grew up with smartphones and social media.

Because the boundaries are judgement calls, you will see ranges that differ by a year or two at each end. Some marketing firms start Gen Z in 1995, some end Millennials in 1994, and McCrindle’s own range for Generation Alpha begins in 2010 rather than 2013. None of these is wrong. They simply reflect different choices about where one shared set of experiences gives way to the next.

Each generation in brief

The Greatest Generation (1901 to 1927)

The name comes from a 1998 book by the American journalist Tom Brokaw. Its members grew up through the Great Depression and many fought in or worked for the Second World War. In 2026 the youngest turn 99, so this generation has almost entirely passed into history.

The Silent Generation (1928 to 1945)

Born during the Depression and the war, when birth rates were low, this is a relatively small generation. The label comes from a 1951 Time magazine essay that described the young people of the day as cautious and quiet. Radio was the family medium in their childhood, and television arrived as they grew up.

Baby Boomers (1946 to 1964)

Named for the surge in births after the war, Boomers were for decades the largest adult generation in the US, with about 76 million American births. They grew up with television, came of age in the 1960s and 1970s, and many watched the Moon landing in 1969 as children or young adults. In 2026 most Boomers are at or past retirement age.

Generation X (1965 to 1980)

Gen X followed the baby boom as birth rates fell, so in the US it is smaller than the generations either side. Its members saw personal computers and video games arrive at home, came of age around the end of the Cold War, and were the first to meet the internet as adults. It is often described as the bridge between an analogue childhood and a digital adulthood.

Millennials (1981 to 1996)

Also called Generation Y, Millennials came of age around the turn of the millennium. The internet and mobile phones arrived in their teens, and many entered the job market around the 2008 financial crisis, which shaped their early careers, home-buying and savings. In 2026 they are aged 30 to 45 and make up a large share of the working population.

Generation Z (1997 to 2012)

Gen Z is the first generation to have had smartphones and social media through most of its teenage years. Many were at school or starting work during the pandemic. In 2026 the oldest are approaching 30, and Gen Z is quickly becoming a major part of the workforce.

Generation Alpha (2013 to 2024)

The first generation born entirely in the 21st century, and the first to grow up with touchscreens, tablets and voice assistants from birth. McCrindle chose the name by moving to the Greek alphabet after Z. In 2026 they are young children and early teenagers.

Generation Beta (2025 to 2039)

The newest generation began in 2025. Its members will grow up with artificial intelligence as an ordinary part of daily life, and many are likely to live into the 22nd century.

How big is each generation?

Generation sizes are often quoted without saying where they come from or which country they mean. The figures below are births, counted from the United Nations’ World Population Prospects series, the same data our calculators use. Births tell you how many people started out in each generation. The number alive today is different, because of deaths and, within a single country, migration.

Two patterns stand out. Worldwide, Gen Z is the largest generation by births, because global births kept rising until the early 2010s and have eased only slightly since. In the United States, Generation X is noticeably smaller than the Boomers before it and the Millennials after it, which is one reason it is sometimes called the “middle child” generation. Generation Alpha looks smaller partly because its range covers only twelve years rather than sixteen, and partly because births have been falling in many countries.

Cuspers and micro-generations

People born within a few years of a boundary often feel they do not fully belong to either side, and they are sometimes called cuspers. Two cusp groups have earned their own informal names. Xennials, born roughly from the late 1970s to the early 1980s, had an analogue childhood but a digital young adulthood, and often remember life before the internet clearly. Zillennials, born roughly in the mid-1990s, sit on the Millennial and Gen Z line and grew up as smartphones were arriving rather than already there.

These micro-generations do not have agreed dates, and that is part of the point. They are a reminder that the change from one generation to the next is gradual. Someone born in 1980 and someone born in 1981 have far more in common than either does with a person born ten years later in the same generation.

What generation labels can and cannot tell you

Generation labels are useful for one thing above all: describing the shared backdrop people grew up against. The technology in the house, the big news events of childhood, the state of the economy when you first looked for work and the prices of homes when you wanted one. Those shared experiences do leave marks that show up in surveys, and they are why the labels have caught on.

They are much weaker as a guide to any individual. Differences within a generation, by country, income, education, family and personal temperament, are usually far larger than differences between generations. Researchers also warn about mixing up age with generation: young adults of every era have tended to move jobs more often and save less, so a habit that looks like a “Gen Z trait” may simply be what people in their twenties do. Pew itself has said it will use generational labels more carefully for this reason.

So the best way to use the chart is as a timeline rather than a personality test. It tells you where your birth year sits in a century of change, which events and inventions arrived when you were young, and how many others started life at the same time. Our calculators for your age when key technologies arrived and for people born the same year take that idea further with your own date.

Questions people ask

Sources. Pew Research Center, “Defining generations: Where Millennials end and Generation Z begins” (2019); US Census Bureau definition of the Baby Boom (1946–1964); McCrindle Research on Generations Alpha and Beta; Strauss and Howe, Generations (1991); United Nations, World Population Prospects 2024, births by year, via Our World in Data.