How this age calculator works (and why it's exact)
Most quick age estimates divide your total days alive by 365.25 — which is fine for trivia but wrong for anything official. This calculator does what a person with a wall calendar would do: it counts complete years from your birth date, then complete calendar months, then the leftover days using the actual length of each month. February gets 29 days in leap years (any year divisible by 4, except century years not divisible by 400), 28 otherwise. That is why the answer here matches passport offices, HR systems, and pension calculations.
Age is one of the few numbers that changes meaning depending on the format. "36 years, 2 months, 8 days" is what a form wants. "13,218 days" is what makes you sit back for a second. Both are the same moment in time — we show you every version at once, including weeks and approximate hours, so you can pick the one that fits.
What the fun facts actually mean
Day of the week born: computed from the calendar itself, not a lookup table — every date since 1900 maps to exactly one weekday. If you want the full folklore ("Monday's child is fair of face…"), see our What Day Was I Born? page.
Western zodiac: based on the sun's position at your birth date, using the standard tropical date ranges (Aries starts March 21, and so on). Boundary dates ("cusps") can shift by a day depending on the year, so if you're born on the edge of a sign, both neighbors are worth reading.
Chinese zodiac: a 12-animal, 5-element cycle. Important caveat: the zodiac year begins at Lunar New Year (between January 21 and February 20), not January 1. If you were born in January or early February, your true animal may be the previous year's — the calculator warns you when that applies.
Generation label: we use the Pew Research Center ranges, the ones journalists and demographers cite most: Silent (1928–1945), Boomer (1946–1964), Gen X (1965–1980), Millennial (1981–1996), Gen Z (1997–2012), Gen Alpha (2013–2024).
Half birthday: your birth date plus exactly six calendar months. Kids with late-summer birthdays swear by it. We have a dedicated half birthday calculator if you want the date of your next one.
Frequently asked questions
How is my exact age calculated?
By calendar arithmetic: complete years, then complete months, then leftover days using real month lengths and leap years — never a 365.25 approximation.
I was born on February 29 — how old am I?
You only get a "real" birthday in leap years, but legally most places treat March 1 as the day you age up in common years, and this calculator follows that convention. Your total-days age is exact regardless.
Why might my Chinese zodiac animal be different if I was born in January or February?
The zodiac year starts at Lunar New Year (Jan 21 – Feb 20), so births before that date belong to the previous animal. The calculator flags this case.
What's a half birthday?
Your birth date plus six calendar months — born March 10 means September 10 is your half birthday.
Which generation am I?
Match your birth year: Boomer 1946–1964, Gen X 1965–1980, Millennial 1981–1996, Gen Z 1997–2012, Gen Alpha 2013–2024.