Rarest Birthdays: All 366 Dates and Adjusted Rankings
How rare is your birthday? Look up all 366 dates in US SSA 2000–2014 data, compare adjusted ranks and see why leap-day totals give a different answer.
Quick Answer
February 29 has fewer opportunities to occur, so it has the lowest total in the US dataset used here. That is different from asking which date has the fewest births each time it occurs. After adjusting for occurrences, December 25 is the least common and September 12 the most common in the SSA 2000–2014 file.
Find your own date: open the birthday rarity lookup. Choose a month and day to see the adjusted rank, recorded births and occurrence count without downloading a spreadsheet. You can also download all 366 rows as CSV.
There is no worldwide top-ten ranking established here. Rankings depend on geography, period and whether leap day is adjusted. Birth statistics also do not establish personality traits or special planetary influences.
The 10 Least Common Dates per Occurrence: US, 2000–2014
| Rank | Date | Mean births per occurrence |
|---|---|---|
| 1 | December 25 | 6437.87 |
| 2 | January 1 | 7735.33 |
| 3 | December 24 | 8034.40 |
| 4 | July 4 | 8815.27 |
| 5 | January 2 | 9605.53 |
| 6 | December 26 | 9874.20 |
| 7 | November 23 | 9875.40 |
| 8 | November 25 | 9978.47 |
| 9 | November 27 | 10012.67 |
| 10 | November 24 | 10024.60 |
The 10 Most Common Dates per Occurrence: US, 2000–2014
| Rank | Date | Mean births per occurrence |
|---|---|---|
| 1 | September 12 | 12734.93 |
| 2 | September 19 | 12695.67 |
| 3 | September 20 | 12541.53 |
| 4 | December 19 | 12445.67 |
| 5 | September 10 | 12444.53 |
| 6 | December 20 | 12439.53 |
| 7 | September 18 | 12425.80 |
| 8 | August 8 | 12421.87 |
| 9 | September 26 | 12421.47 |
| 10 | September 17 | 12386.13 |
Method: sum births for each month/day across the US Social Security Administration 2000–2014 file, then divide by the number of times that date occurs in the file. Each ordinary date occurs 15 times; February 29 occurs 4 times. Its 41,869 total births become 10467.25 births per occurrence. It has the lowest total because it occurs less often, but it is not the least common by this adjusted measure.
Source: FiveThirtyEight's published SSA CSV, retrieved 2026-10-23. This is one US dataset, not a worldwide ranking. The separate CDC 1994–2003 dataset overlaps in years and is not merged into these figures.
How Rare Is My Birthday? Read the Rank Correctly
Find the month and day in a dataset that names its population and years. Then check whether the ranking uses total births or mean births per occurrence. Those are different questions, especially for February 29.
In the table above, an ordinary date occurs fifteen times and leap day occurs four times. Dividing by those occurrence counts makes the comparison about how many births happened when the date was available. It does not estimate the chance that a randomly selected person alive today shares your birthday.
A birthday-rarity checker using different years or a different population can give another rank. Compare the source and counting method before comparing the number. A low-ranked date in one sample is not automatically one of the rarest birthdays worldwide.
Look Up Any of the 366 Birthdays
The browser birthday lookup covers every date, including February 29. It uses the same source and adjusted ranking as this article; your birth year is not an input because the comparison groups month/day across the full sample. Its expandable table also lets you browse all 366 rows.
The top-ten tables cannot tell you where every other date falls. Download the complete 366-date birthday ranking as a CSV, then find your month and day in the month_day column. The file opens in a spreadsheet and includes total births, occurrence counts, mean births per occurrence and rank_rarest_first: rank 1 is the least common by the adjusted measure.
For a worked example, February 29 has 41,869 births across four occurrences, or 10,467.25 per occurrence. December 25 has 96,568 across fifteen occurrences, or 6,437.87 per occurrence. Leap day has the smaller total; December 25 has the smaller adjusted mean. Both statements can be true because their denominators differ.
The download uses the same SSA 2000–2014 source as the tables. It is a historical sample, not a worldwide population estimate, a prediction for this year or a measure of how rare your complete birth chart is.
Three Birthday Lookup Examples
These examples show how to read the US SSA 2000–2014 ranking:
| Birthday | Adjusted rank, least common first | Recorded births | Occurrences | Mean births per occurrence |
|---|---|---|---|---|
| January 17 | 170 of 366 | 169,280 | 15 | 11,285.33 |
| May 23 | 307 of 366 | 178,891 | 15 | 11,926.07 |
| June 21 | 251 of 366 | 174,078 | 15 | 11,605.20 |
Rank 1 means the smallest mean, not the most popular date. May 23 therefore has more births per occurrence than January 17 in this sample. These ranks do not justify a worldwide “rare” label or a claim about the percentage of people alive today. Look up another birthday to compare the same measure.
Why Holidays Matter
The Office for National Statistics analysis of England and Wales, 1995–2014 also finds a Christmas and New Year dip. ONS suggests that scheduling induced births and elective caesareans away from holidays helps explain it. That is a proposed practical explanation, not a cosmic one.
ONS identifies September 26 as the most popular date in that population and period. Its result differs from this US table, which is why a country and date range belong beside any ranking.
February 29: Calendar Rarity
In the Gregorian calendar there are 97 leap days in a 400-year cycle of 146,097 days. Years divisible by 100 are not leap years unless also divisible by 400: 2000 was a leap year, while 2100 will not be. The familiar one-in-1,461 approximation describes a four-year interval without a skipped century leap day; it is not the exact long-run calendar frequency.
A day’s calendar frequency does not by itself establish what fraction of the living population shares that birthday. That would require birth records, survival and population coverage. We do not give a worldwide leapling population estimate here.
For modern dates in the tropical zodiac, a February 29 Sun lies in Pisces. That identifies a zodiac position, not evidence that leap-day people have stronger Neptune or Jupiter influences in the rest of their charts.
Keeping Astrology Separate From Statistics
An astrologer may associate Pisces with imagination or Capricorn with structure. These are symbolic meanings. The birth tables above do not test them, and a rare birthday does not make a full chart more powerful or spiritually significant.
Holiday customs can also shape personal experience. Someone may enjoy a shared celebration or dislike having a birthday overshadowed by it. Ask about that person's experience rather than inferring it from a date.
Seasonal language needs a hemisphere: December follows the winter solstice in the Northern Hemisphere and the summer solstice in the Southern Hemisphere. The tropical Sun is in Capricorn in both.
How Rare Is My Birth Chart?
A birthday rank cannot answer that question. “Birth chart rarity” needs a definition of what matches: the same Sun sign, the same ten planetary signs, positions within a stated degree tolerance, or the same houses and angles. Those comparisons have different denominators. Planetary positions are also related by their motions, so multiplying simple sign percentages is not a reliable shortcut to a full-chart probability.
A birthday supplies only part of the input for a natal chart. The year, time and place determine the rest of the sky calculation. Houses and angles require a sufficiently accurate time; even planetary signs need checking on ingress dates.
Calculate your birth chart if you want to inspect those positions. You can inspect its actual signs, degrees and supported houses, or use the stellium counting guide to check one specific grouping. These are defined chart features, not a validated rarity score. Its geometry does not establish how rare the whole chart is in a population. A birthday ranking cannot supply that probability either.
A Birthday Reflection Exercise
- Look up a statistic with its country, period and counting method.
- Separate what the numbers show from any meaning you personally assign to the date.
- Ask what sharing a holiday or celebrating leap day has actually been like for you.
- If you use the solar return calculator, remember that it calculates a return to the natal Sun longitude, not necessarily a calendar-birthday anniversary time.
The statistics describe a population and a calendar. The reflection belongs to you. Neither requires a claim that the date determines your character or future.
Frequently Asked Questions
Is February 29 the rarest birthday?
It is the least frequent calendar date and has the lowest total births in the file used here. Once births are divided by the number of times each date occurs, December 25 has the lowest mean in this dataset. Always state which measure you mean.
Why do rare-birthday lists disagree?
They can use different populations, years, coverage and leap-day adjustments. A ranking based on totals is not interchangeable with one based on births per occurrence. The source and method beside the table are part of the answer, not optional footnotes.
What is the rarest birthday in the world?
This article does not establish a worldwide ranking. The tables describe one published dataset and period. A global claim would need comparable birth records with suitable geographic and time coverage.
Does a rare birthday mean a rare birth chart?
No. A month/day ranking does not measure the frequency of an entire chart. Planetary positions also depend on year and time, and houses depend on time and place. The full birth chart shows those calculated placements without assigning an unsupported rarity percentage.
How can I find my birthday if it is not in the top ten?
Use the complete CSV linked above and search for your date in month-day form, such as 02-29. Check the adjusted rank rather than sorting total births alone. All 366 calendar dates are included, with the sample period and occurrence counts. Your result describes this dataset; a different population or period can produce another rank.
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Source: Natal Echo (natalecho.com) — https://natalecho.com/learn/astrology/rarest-birthdays-in-the-world-stats-and-astrological-meaning. Published by Natal Echo at natalecho.com; please cite Natal Echo (natalecho.com) when quoting or reusing this guide.