The rarest birthdays in the U.S.

The top 100 rarest birthdays in these historical U.S. records run from February 29 to April 17. February 29 is the least common birthday, with the fewest total births. Excluding leap day, December 25 is the least common birthday. Compare both totals and births per occurrence below.

85,712,738 U.S. births. 1994–2014 · CDC/NCHS + SSA. Sources & method

See the top 100 rarest birthdays or find your birthday among all 366 dates

February 29 is the rarest birthday.

52,561 of the 85,712,738 recorded U.S. births fell on February 29. That’s 0.061% of births in 1994–2014. This ranking uses total births across the full period.

Excluding leap day, December 25 has the fewest births in these records. The controls below let you explore both views.

Find your birthday in the full list

1. 01 February 29 0.061%
2. 02 December 25 0.162%
3. 03 January 1 0.192%
4. 04 December 24 0.199%
5. 05 July 4 0.216%
6. 06 January 2 0.229%
7. 07 December 26 0.235%
8. 08 November 27 0.239%
9. 09 November 23 0.243%
10. 10 November 25 0.245%

Leap day occurs less often than other dates.

Leap day has fewer calendar occurrences. In 1994–2014, it occurs five times. Other dates occur 21 times. A total-based ranking includes that difference.

Switch to “Births per occurrence” to compare an average appearance of each date, or exclude February 29 to look at the other 365 days.

Read the full leap-day comparison.

Printable top 100 rarest birthdays

The list starts with February 29, December 25, and January 1. It ranks dates by total recorded U.S. births from 1994–2014.

A separate SSA 2000–2014 study uses five-year periods and excludes February 29. Its top-100 lists change with the period and measure. Compare annual shares, weekday ratios, and raw counts in the ranking-stability study.

Ordered by total recorded U.S. births, 1994 through 2014, including February 29. Download the printable image or get the CSV with counts and measures. The full ranking below lets you switch measures and exclude leap day.

Preview the printable list

Leap day: totals and births per occurrence

February 29 has 52,561 recorded births in this U.S. dataset for 1994–2014. It has the fewest total births among all 366 dates.

Dividing 52,561 births by five occurrences gives 10,512.2 births per occurrence. On this measure, February 29 is 20th-rarest among 366 dates.

This average uses only five leap days. It does not adjust for weekdays or years, and it does not establish a universal birth rate.

Download the full-size comparison or read the pinned source data. The table below lists the values. The methodology explains both measures.

How rare is a February 29 birthday, really?

February 29 accounts for 0.0613% of recorded births, or about 1 in 1,631, in the U.S. data used by Birthday Odds. The records contain 52,561 leap-day births out of 85,712,738 births from 1994 through 2014.

It has the fewest total births of all 366 birthday dates. But February 29 appeared only 5 times during those 21 years: 1996, 2000, 2004, 2008, and 2012. Every other month/day appeared 21 times.

What changes when you count births per occurrence?

Divide the 52,561 leap-day births by those 5 actual February 29 dates. That gives an average of 10,512.2 births each time the date occurred.

February 29 has the smallest share of all recorded births in the table. An actual leap day, however, averaged more births than Christmas Day (6,601.3) or New Year's Day (7,826.8). September 9 is included as a high-frequency comparison, with 12,344.2 births per occurrence.

Its average per actual appearance is 59.2% above Christmas Day's. That does not make a leap-day birthday more common overall: February 29 had only five appearances, while Christmas had 21.

On that measure, February 29 moves from rank #366 to #347 out of 366, where #1 means the most births. 19 dates have a lower average per occurrence. Leap day is still near the rare end of the ranking.

Total births tell you how often February 29 appears among the recorded birthdays. The per-occurrence average answers a different question: how many births happened on the date when it existed? Its share of all recorded births stays at 0.0613%.

Why do people say the odds are 1 in 1,461?

A simple four-year cycle has 365 + 365 + 365 + 366 = 1,461 days, including one February 29. If every day had the same number of births, leap day would account for 1 in 1,461 births over that cycle.

That calculation assumes equally frequent births across a four-year cycle. Our records span 21 years, and birth counts vary across days and years.

For this exact period, an equal-births-per-day reference would use five leap days out of 7,670 actual days: 0.0652%, or 1 in 1,534. The observed share is 0.0613%, or about 1 in 1,631. These equal-day calculations are calendar references; the birth records give a different result.

The Gregorian calendar also skips some century leap years: a century year must be divisible by 400 to qualify. The U.S. Naval Observatory explains the leap-year rule.

Compare leap day with your birthday

In the ranking above, choose "Births per occurrence" to compare the average for each date. Excluding February 29 answers another useful question: which birthday is rarest among dates that occur every year?

You can also check February 29 directly or explore birth counts around selected holidays.

Sources and limits for this comparison

The counts come from FiveThirtyEight's historical U.S. birth files: CDC/NCHS for 1994 through 1999 and SSA for 2000 through 2014. The methodology explains source overlap and the calculations.

Dividing by occurrences adjusts for how often the date appears. It does not adjust for which weekdays or years those five leap days fell in. These historical records describe the births counted in this dataset; they do not estimate the birthdays of everyone alive today or a particular baby's chance of arriving on leap day.

What are the top 100 rarest birthdays?

With "Total births" selected and February 29 included, the ranking above runs from the rarest date first to the most common last. Its first 100 rows are the top 100 rarest dates in these historical U.S. records. The 100th is April 17, with 229,783 recorded births.

A row's position in the rarest-first list differs from its commonness rank. The first row is February 29, with commonness rank #366. The 100th row has commonness rank #267. Commonness rank #1 means most common, so a larger number indicates fewer births. "Top 100" selects a convenient length of list; it is not a statistical boundary between rare and ordinary birthdays.

Download the 100 rarest birthdays as a CSV. It includes rarest-first positions, date labels, totals, commonness ranks, shares and actual-occurrence averages. The download uses total births with leap day included, regardless of settings you change in the interactive table.

If you exclude February 29, December 25 becomes the first date and May 30 enters at the end of the first 100. Switching to births per occurrence changes leap day's position again. Clear the search field before browsing a full 100-date list; searching a date narrows the rows, rather than creating a new rarity ranking.

Each date in the table links to its birthday-checker result. The methodology explains both measures. All these ranks describe the selected 1994 through 2014 records, not living populations or worldwide birthday odds.

For age and celebration questions, read leap-day birthdays. The February 28 study also separates leap years from common years; these are different comparisons from ranking February 29 by total births.

A little more birthday curiosity.