π Date of Birth Facts
Weekday born, exact age, zodiac, birthstone, and more.
Born on a
How to Use This Calculator
Enter the birth date and hit Get Birth Facts. The headline names the weekday of birth; the details stack the exact age in years, months, and days, the Western zodiac sign, the birthstone, the Chinese zodiac animal, the generation, and the days until the next birthday. Set the "as of" date to answer "how old was I when" for any past date. Everything derives from the one date you enter, cross-checked against standard calendar and zodiac tables.
Enter the full birth date. Day and month drive the zodiac and weekday results.
Optionally set an "as of" date for historical age questions.
Hit Get Birth Facts and read the weekday headline plus the full details.
Use the age breakdown for forms and the fun facts for cards and posts.
The Method: One Date, Many Tables
The weekday comes from the date's position in the Gregorian calendar, computed the same way date libraries do it, which automatically respects leap years and the century rules. Age uses the same calendar-subtraction method as the age calculators: completed years, then months and days from the last birthday. The Western zodiac is a simple date-range lookup on month and day. Birthstones follow the modern American list standardized in 1912. The Chinese zodiac cycles every 12 years anchored so that the remainder math lands correctly: 2026 is the Horse, and the formula reproduces that. Generation labels follow the commonly used Pew ranges. Each table is independent, so one wrong input cannot corrupt the others.
Worked Example
Birth date August 12, 1995, measured October 16, 2026. Weekday: August 12, 1995 was a Saturday. Age: 31 years, 2 months, 4 days. Zodiac: Leo (July 23 to August 22). Birthstone: peridot. Chinese zodiac: 1995 is the Pig. Generation: Millennial. Next birthday: August 12, 2027, 300 days away. Enter the date above and each fact matches. The cross-check that builds trust: August 12, 1995 really was a Saturday, verifiable against any perpetual calendar, which confirms the calendar math everything else stands on.
Zodiac Signs and Their Dates
The tropical zodiac used in Western astrology divides the year into twelve roughly equal signs starting at the March equinox: Aries (Mar 21-Apr 19), Taurus (Apr 20-May 20), Gemini (May 21-Jun 20), Cancer (Jun 21-Jul 22), Leo (Jul 23-Aug 22), Virgo (Aug 23-Sep 22), Libra (Sep 23-Oct 22), Scorpio (Oct 23-Nov 21), Sagittarius (Nov 22-Dec 21), Capricorn (Dec 22-Jan 19), Aquarius (Jan 20-Feb 18), Pisces (Feb 19-Mar 20). Cusp birthdays within a day of a boundary vary by source and year; the calculator uses the standard boundaries. Treat it as entertainment with fixed rules, which is exactly what it is.
Birthstones by Month
January garnet, February amethyst, March aquamarine, April diamond, May emerald, June pearl (or moonstone), July ruby, August peridot, September sapphire, October opal (or tourmaline), November topaz (or citrine), December turquoise (or zircon). The list was standardized by American jewelers in 1912 and tweaked since; the parenthetical alternates are official modern additions. Birthstone jewelry is a safe gift precisely because the lookup is unambiguous: the month decides, taste decides the setting.
Birth Certificates: Getting It Right
The birth certificate is the root document everything else derives from: Social Security, passports, licenses. Errors on it propagate for decades, so verify the hospital's worksheet before it is filed: spelling of names, date, time, and place. Correcting later means affidavits, fees, and months of waiting, varying wildly by state. If you were born abroad to US citizen parents, the equivalent root document is the Consular Report of Birth Abroad, not a foreign certificate alone. Keep certified copies (not photocopies) in two places: a fire safe and with a trusted person or in secure storage. You will need them for first passports, Real ID licenses, and many background checks. Order extras from the vital records office of the birth state or country; hospitals do not keep issuing them.
Age Verification and Privacy
Your date of birth is both an identifier and a authenticator, which makes it a prime target. Data brokers trade it freely, and combined with your name it unlocks account recovery flows at careless companies. Minimize exposure: do not post your real birth date on social media (birthday posts are social engineering fuel), and question forms that demand it without a clear legal need. When a site requires an age gate, it needs your age, not your identity; consider whether the full date is truly required. For your own calculations, this tool runs entirely in your browser: your birth date never leaves the page. That is the standard you should expect from any online calculator handling personal data: client-side computation, no accounts, no tracking.
A Second Worked Example: The Centenarian
Born March 15, 1926, measured October 16, 2026: exactly 100 years, 7 months, 1 day. Western zodiac: Pisces (February 19 to March 20). Birthstone: aquamarine for March. Chinese zodiac: (1926 minus 4) mod 12 is 2, which maps to Tiger. Generation: the Greatest Generation, born roughly 1901 to 1927. Days until the 101st birthday: from October 16, 2026 to March 15, 2027 is 150 days. A century of life, summarized in one calculation.
Centenarian math is where the tables shine together. The weekday of birth, the zodiac signs, the generation label, and the exact age each answer a different question the family asks at the party. Run the calculator once and you have the toast, the card, and the trivia covered.
Generation Labels: Useful Shorthand, Blurry Edges
The generation names everyone uses follow roughly these ranges: Greatest (1901-1927), Silent (1928-1945), Boomers (1946-1964), Gen X (1965-1980), Millennials (1981-1996), Gen Z (1997-2012), Gen Alpha (2013 onward). They are shorthand for shared historical context, not personality tests. A 1980 baby and a 1982 baby had nearly identical childhoods despite the label change.
Treat the edges as fuzzy, because they are. Researchers argue about the exact cutoffs, and different organizations publish slightly different ranges. The labels are most useful for demographics and marketing, least useful for judging individuals. Nobody is a stereotype with a birth year, and the calculator reports the label as a fun fact, which is all it should ever be.
Common DOB Fact Mistakes
First: zodiac cusp confusion. The sign changes on specific dates, and being born on March 20 versus March 21 can flip Pisces to Aries. There are no "cusp signs" in the standard tropical system; the date decides. Second: mixing tropical and sidereal zodiacs. Western astrology uses the tropical zodiac tied to seasons; Vedic astrology uses the sidereal zodiac tied to constellations, and they are about 24 degrees apart. Same birthday, different sign, different system.
Third: birthstone list variants. The modern US list (1912) differs from traditional and mystical lists; October is opal modern but tourmaline gets added in some versions. State which list you mean. Fourth: generation edge years. Being born in 1996 versus 1997 changes the label but not the person. Fifth: weekday confidence. People misremember their birth weekday constantly; the calendar math does not. Trust the calculator over family lore.
Frequently Asked Questions
What day of the week was I born?
Enter your birth date above and the calculator shows the weekday instantly. It uses real calendar math, so leap years and century rules are handled. About 1 in 7 people were born on each weekday, though hospital data shows slightly fewer weekend births due to scheduled deliveries.
How do I find my zodiac sign?
Western zodiac signs follow fixed date ranges (Aries starts March 21, Taurus April 20, and so on through Pisces ending March 20). The calculator assigns yours automatically from your birth date, including the cusp-day edge cases. If you were born on a boundary day, check an ephemeris for your birth year, since exact cusp times shift slightly year to year.
What is my birthstone?
The modern US list: January garnet, February amethyst, March aquamarine, April diamond, May emerald, June pearl or moonstone, July ruby, August peridot, September sapphire, October opal, November topaz or citrine, December turquoise or zircon. The calculator shows yours with the other birth facts.
How old was I on a specific date?
Set the "as of" date to any past date and the calculator reports your age then, in years, months, and days. This answers "how old was I when" questions for records, eligibility, and trivia. Leave it empty to calculate against today.
What is my Chinese zodiac animal?
Chinese zodiac cycles every 12 years: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig. The year 2026 is the Year of the Horse. The calculator includes your animal based on birth year. Note the Chinese New Year moves between January 21 and February 20, so January and February birthdays near the boundary need the exact new year date.
How many days until my next birthday?
The calculator counts it automatically, rolling to next year if this year's birthday passed. February 29 birthdays count to March 1 in common years. The countdown is exact calendar days, which is what you want for party planning and the "days until" social post.
Why do I need my exact birth date for forms?
Because age thresholds are date-precise: voting, drinking, retirement, and school cutoffs all key off the full date, not the year. Two people born in 2008 can be on opposite sides of a cutoff. The calculator's years-months-days breakdown matches how official systems compute eligibility.
What generation does my birth date put me in?
The calculator shows the generation label from your birth year: Gen Z for 1997 to 2012, Millennial for 1981 to 1996, Gen X for 1965 to 1980, Boomer for 1946 to 1964. It is cultural shorthand, not destiny, but it is the fastest way to place a birth year in context.