About BirthdayHub
BirthdayHub brings together everything about your birthday — birthstone, birth flower, birth color, zodiac, Chinese zodiac, Japanese era, yakudoshi, life milestones and famous people who share your day.
About our data
Birthstones
Monthly birthstones are based on widely recognized traditional associations. Assignments can vary by country and organization, and some months have more than one stone.
Birth flowers & colors
There is no single official standard for birth flowers or birth colors; sources differ. We present a representative selection for each month (not a 365/366-day list).
Notable days
We list only days with a fixed Gregorian date that can be verified — holidays, international days and seasonal traditions. Movable observances whose dates change each year are excluded to avoid showing an incorrect date.
Zodiac, Chinese zodiac, Japanese era, yakudoshi & famous people
Based on common calculation methods and public references. Customs such as yakudoshi may vary by region and tradition.
Numerology, Nine Star Ki, biorhythm & element compatibility
Life Path Numbers and the Personal Year (your yearly cycle, 1→9 over nine years) follow standard Western numerology, the honmei star follows Nine Star Ki, compatibility follows classical element pairings in Western astrology, and biorhythm (physical 23, emotional 28, intellectual 33 days) is an early-20th-century concept. All follow the standard rules of their systems, calculated deterministically from your birth date (the Personal Year from your birth month/day plus the given year); we never invent custom scores or labels. None are scientific claims, and every display names its source tradition.
Gemstone meanings
There is no official standard for stone meanings or lore; we present widely known traditions. Mohs hardness and mineral groups are standard mineralogy. Nothing here is a claim of effect.
Birthday statistics (trends & rarity)
The birth-month trend, “how many share your birthday”, and birthday rarity (rank out of 366) are based on real official birth statistics, not fortune-telling. Sources: Japan — MHLW Vital Statistics (births by month); United States — CDC/NCHS and SSA (daily, 2000–2014, published by FiveThirtyEight); population — Japan’s MIC population estimate and the UN world population. The daily rarity uses US data; other countries show similar seasonality but exact ranks differ by country and year. “People who share your birthday” is an estimate assuming an even distribution; we do not invent or interpolate figures.
Generation
The generation derived from your birth year (Baby Boomers, Gen X, Millennials, Gen Z, etc.) is a social-statistical classification, not fortune-telling. Ranges follow the widely cited Pew Research Center definitions, with commonly used ranges for the oldest (pre-Silent) and newest (Alpha, Beta) cohorts. Generation boundaries vary by source, and the descriptions cover only the era of birth — not personality.
Moon sign, birth chart & Rokuyo (precise astronomy)
The Moon sign, birth chart (planets in signs) and Rokuyo are computed with a precise astronomy engine (astronomy-engine), deriving each body's position and the new moons / solar terms. The positional and calendrical math is exact, not an approximation. However, the astrological and Rokuyo interpretations are cultural traditions, not scientific claims. The Moon, Mercury and Venus move fast, so on boundary days the sign depends on birth time. The Ascendant and houses require birth time and place and are not offered.
How to use this
The information here is offered for general interest and entertainment. We aim for accuracy, but it is not intended as a basis for medical, financial or official decisions.
Frequently Asked Questions
Is there only one birthstone per month?
We list a representative stone for each month, but assignments vary by country and organization, and some months have more than one stone.
Is there an official standard for birth flowers and colors?
No. There is no single official standard, and sources differ. We present a representative selection for each month.
How are the "notable days" chosen?
We include only days with a fixed Gregorian date that can be verified — holidays, international days and seasonal traditions. Movable observances whose dates change each year are excluded.
Is any of the astrology or numerology scientifically proven?
No. Zodiac signs, numerology, Nine Star Ki, element compatibility, biorhythm and stone meanings are cultural traditions, not science, and we make no scientific claims. What we do instead: we never invent custom scores or labels, and every display names the tradition it comes from.
Are some birthdays more common than others?
Yes. In real birth data, more people are born in late summer to early autumn (around September), while year-end, Christmas, holidays and the leap day Feb 29 are less common (elective deliveries are avoided). Our “birthday rarity” ranking uses real US SSA data (2000–2014) over all 366 days, not a made-up score; other countries are similar but exact ranks differ by country and year.
How are the Moon sign and birth chart calculated?
We compute the positions of the celestial bodies on your birth date with a precise astronomy engine. The Sun, Mars, Jupiter and Saturn are essentially fixed by your birth date, while the Moon, Mercury and Venus move fast — on boundary days the sign depends on birth time. The Ascendant and houses need birth time and place, so we do not offer them. Astrology, not a scientific claim.
How should I use this information?
It is offered for general interest and entertainment. We aim for accuracy, but it is not intended as a basis for medical, fortune-telling or official decisions.