{
  "id": "lunar-age",
  "version": "2333d1d08ef3",
  "status": "published",
  "name": "Lunar Age Calculator",
  "question": "What is my lunar age?",
  "summary": "Works out your Chinese lunar age (nominal age): 1 at birth and one more at every Lunar New Year, with the Korean traditional age, your zodiac animal and the next birthday of the count.",
  "category": "days",
  "subcategory": "age",
  "url": "https://www.acalculator.org/days/lunar-age-calculator",
  "markdown": "https://www.acalculator.org/days/lunar-age-calculator.md",
  "kind": "function",
  "method": "Y(d) = the Gregorian year of d, less 1 if d is before that year’s Lunar New Year; lunar age = Y(age-on date) − Y(birth) + 1; Korean traditional age = year(on) − year(birth) + 1.",
  "assumptions": [
    "Lunar New Year is the first day of the first month of the Chinese calendar, in China time (UTC+8), as the Hong Kong Observatory publishes it.",
    "Dates from 1930 to 2100.",
    "Some families count the extra year from the start of spring (Lichun, about February 4) instead; this page uses Lunar New Year."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "birth": {
        "title": "Date of birth",
        "description": "Your date of birth on the Gregorian calendar.",
        "type": "string",
        "format": "date"
      },
      "on": {
        "title": "Age on",
        "description": "The date to count the age on. Today, unless you change it.",
        "type": "string",
        "format": "date"
      }
    }
  },
  "outputs": {
    "lunar": {
      "label": "Lunar age",
      "description": "The Chinese nominal age: 1 at birth, plus 1 at each Lunar New Year since.",
      "format": "integer"
    },
    "age": {
      "label": "Age in whole years",
      "description": "The usual (international) age: whole years since birth.",
      "format": "integer"
    },
    "korean": {
      "label": "Korean traditional age",
      "description": "1 at birth, plus 1 every January 1.",
      "format": "integer"
    },
    "animal": {
      "label": "Zodiac animal",
      "description": "The animal of the Chinese year you were born in.",
      "format": "text"
    },
    "nextNewYear": {
      "label": "Next Lunar New Year",
      "description": "The next Lunar New Year after the age-on date, when the lunar age goes up by 1.",
      "format": "date-long"
    },
    "lastNewYear": {
      "label": "Lunar New Year of this year",
      "description": "The Lunar New Year that started the Chinese year of the age-on date.",
      "format": "date-long"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "birth": "1995-06-15",
      "on": "2026-10-05"
    },
    "outputs": {
      "lunar": 32,
      "age": 31,
      "korean": 32,
      "animal": "Pig",
      "nextNewYear": "2027-02-06",
      "lastNewYear": "2026-02-17"
    },
    "text": "Born on June 15, 1995, your lunar age is 32 (31 in whole years)."
  },
  "examples": [
    {
      "given": {
        "birth": "1995-06-15",
        "on": "2026-10-05"
      },
      "expect": {
        "lunar": 32,
        "age": 31,
        "korean": 32,
        "animal": "Pig",
        "nextNewYear": "2027-02-06",
        "lastNewYear": "2026-02-17"
      },
      "source": "hand calculation in content.mdx: 2026 − 1995 + 1 = 32; Wikipedia, Chinese zodiac (start dates of each year from 1924 to 2043; 2020 is a Rat year), https://en.wikipedia.org/wiki/Chinese_zodiac (retrieved 2026-10-05); Wikipedia, East Asian age reckoning (a newborn is 1; Chinese nominal age adds a year at the Lunar New Year, the traditional Korean count on January 1), https://en.wikipedia.org/wiki/East_Asian_age_reckoning (retrieved 2026-10-05)"
    },
    {
      "given": {
        "birth": "2000-01-20",
        "on": "2026-01-10"
      },
      "expect": {
        "lunar": 27,
        "age": 25,
        "korean": 27,
        "animal": "Rabbit",
        "nextNewYear": "2026-02-17",
        "lastNewYear": "2025-01-29"
      },
      "source": "hand calculation in content.mdx: 2025 − 1999 + 1 = 27; Wikipedia, Chinese zodiac (start dates of each year from 1924 to 2043; 2020 is a Rat year), https://en.wikipedia.org/wiki/Chinese_zodiac (retrieved 2026-10-05); Wikipedia, East Asian age reckoning (a newborn is 1; Chinese nominal age adds a year at the Lunar New Year, the traditional Korean count on January 1), https://en.wikipedia.org/wiki/East_Asian_age_reckoning (retrieved 2026-10-05)"
    },
    {
      "given": {
        "birth": "2026-02-16",
        "on": "2026-02-17"
      },
      "expect": {
        "lunar": 2,
        "age": 0,
        "korean": 1,
        "animal": "Snake"
      },
      "source": "hand calculation in content.mdx; Wikipedia, Chinese zodiac (start dates of each year from 1924 to 2043; 2020 is a Rat year), https://en.wikipedia.org/wiki/Chinese_zodiac (retrieved 2026-10-05); Hong Kong Observatory, Gregorian-Lunar Calendar Conversion Table (1st Lunar Month dates), https://www.hko.gov.hk/en/gts/time/conversion1_text.htm (retrieved 2026-10-05); Wikipedia, East Asian age reckoning (a newborn is 1; Chinese nominal age adds a year at the Lunar New Year, the traditional Korean count on January 1), https://en.wikipedia.org/wiki/East_Asian_age_reckoning (retrieved 2026-10-05)"
    },
    {
      "given": {
        "birth": "1954-02-03",
        "on": "1954-02-03"
      },
      "expect": {
        "lunar": 1,
        "korean": 1,
        "animal": "Horse",
        "nextNewYear": "1955-01-24"
      },
      "source": "Wikipedia, Chinese zodiac (start dates of each year from 1924 to 2043; 2020 is a Rat year), https://en.wikipedia.org/wiki/Chinese_zodiac (retrieved 2026-10-05) (1954 starts on February 3); hand calculation in content.mdx"
    }
  ],
  "sources": [
    "Wikipedia, East Asian age reckoning: the nominal age count in China and the Korean count. https://en.wikipedia.org/wiki/East_Asian_age_reckoning (retrieved 2026-10-05)",
    "Wikipedia, Chinese zodiac: the start date of each Chinese year from 1924 to 2043. https://en.wikipedia.org/wiki/Chinese_zodiac (retrieved 2026-10-05)",
    "Hong Kong Observatory, Gregorian-Lunar Calendar Conversion Table: the first day of the 1st lunar month each year. https://www.hko.gov.hk/en/gts/time/conversion1_text.htm (retrieved 2026-10-05)"
  ],
  "related": [
    "birthday",
    "dob",
    "chronological-age"
  ],
  "changelog": []
}