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Generation by Birth Year Calculator

Q: Why do other sources give different years?

There is no official standard. Pew's boundaries are the most cited in the US press; McCrindle uses uniform 15-year spans (e.g. Generation Z 1995–2009), and the US Census Bureau only defines the Baby Boom (1946–1964).

Q: What about Xennials or Zillennials?

They are informal micro-generations on the cusps (roughly 1977–1983 and 1993–1998). This tool flags the first and last two years of each generation as cusp years instead.

Classifies a birth year into its named generation using the Pew Research Center birth-year boundaries (Silent 1928–1945, Baby Boomers 1946–1964, Generation X 1965–1980, Millennials 1981–1996, Generation Z 1997–2012), extended with the Lost and Greatest generations and McCrindle's Generation Alpha and Beta, and reports the age reached in a reference year and the position within the generation.

When to use

You need the named generation for a birth year, its year range and neighbours, whether the person is early, mid or late in the cohort, or how old that generation is in a given year.

Do not use when: You need an exact age in years, months and days (use age) or a zodiac sign (use zodiac); generation boundaries are research conventions that differ by a few years between sources, so do not treat them as official.

Formula

generation = range containing birth_year: Lost 1883–1900, Greatest 1901–1927, Silent 1928–1945, Baby Boomers 1946–1964, Generation X 1965–1980, Millennials 1981–1996, Generation Z 1997–2012, Generation Alpha 2013–2024, Generation Beta 2025–2039; age_in_reference_year = year(reference_date) − birth_year; position: f = (birth_year − first_year + 0.5) / span → Early (f < 1/3), Mid, Late (f ≥ 2/3)

Silent through Generation Z use the Pew Research Center boundaries (Generation Z end year 2012); Lost and Greatest follow the Wikipedia 'Generation' overview; Generation Alpha is started in 2013 so that the timeline has no gap after Pew's Generation Z (McCrindle, who coined the name, uses 2010–2024) and Generation Beta 2025–2039 follows McCrindle. People born within a year or two of a boundary are commonly described as being on the cusp.

Inputs

Parameter	Type	Unit	Required	Description
`birth_year`	integer		yes	Year of birth, 1883–2039. Range: ≥ 1883, ≤ 2039
`reference_date`	date		default today	Date whose year is used for the age; defaults to the current UTC date.

Outputs

Output	Type	Unit	Description
`generation`	string		Name of the generation.
`generation_years`	string		First–last birth year of the generation, e.g. 1981–1996.
`age_in_reference_year`	integer	years	Year of reference_date − birth_year (the age reached during that year; negative if not yet born).
`position_in_generation`	string		Early, Mid or Late (thirds of the generation's span), with a cusp note in the first or last two years.
`neighbouring_generations`	string		The generations immediately before and after, with their years.
`generation_age_range`	string		Youngest–oldest age of the whole generation in the reference year.
`source_note`	string		Whose boundaries define this generation.

Example

Born 1990, reference year 2026: {"birth_year":1990,"reference_date":"2026-09-24"} → {"generation":"Millennials","generation_years":"1981–1996","age_in_reference_year":36,"position_in_generation":"Mid","neighbouring_generations":"Preceded by Generation X (1965–1980); followed by Generation Z (1997–2012)","generation_age_range":"30–45"}

Born 2005, reference year 2026: {"birth_year":2005,"reference_date":"2026-09-24"} → {"generation":"Generation Z","generation_years":"1997–2012","age_in_reference_year":21,"position_in_generation":"Mid","generation_age_range":"14–29"}

GET https://tttkmbb.com/api/v1/calculate/generation-by-birth-year?birth_year=1990&reference_date=2026-09-24

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/generation-by-birth-year (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/generation-by-birth-year · Markdown: https://tttkmbb.com/everyday/generation-by-birth-year.md · JSON definition: https://tttkmbb.com/everyday/generation-by-birth-year.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="generation-by-birth-year"
OpenAPI operationId: classify_generation_by_birth_year
Freshness: daily. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

Why do other sources give different years?

There is no official standard. Pew's boundaries are the most cited in the US press; McCrindle uses uniform 15-year spans (e.g. Generation Z 1995–2009), and the US Census Bureau only defines the Baby Boom (1946–1964).

What about Xennials or Zillennials?

They are informal micro-generations on the cusps (roughly 1977–1983 and 1993–1998). This tool flags the first and last two years of each generation as cusp years instead.

Related calculators

Age Calculator — Exact age in years, months and days.
Zodiac Sign Calculator — Western and Chinese zodiac signs for a birth date.