All 366 days, ranked with real data
Birthday Rarity Ranking
How rare is your birthday? Using real month-day birth counts from Japan's Vital Statistics (2015-2024, Ministry of Health, Labour and Welfare), we ranked all 366 birthdays including February 29.
The 366-day heatmap calendar
Darker days have more birthdays. Pick any cell to open that day's page.
FewerMore
Color = sextile of average births per year (6 levels of 61 days each). February 29 is averaged over the three leap years (2016, 2020, 2024).
Top 10 most common birthdays
- 1January 52,820
- 2May 22,719
- 3September 202,677
- 4August 82,665
- 5April 272,664
- 6September 282,653
- 7September 262,649
- 8September 252,644
- 9September 272,640
- 10May 12,638
Top 10 rarest birthdays
- 1January 11,475
- 2January 21,487
- 3December 311,504
- 4January 31,597
- 5November 231,638
- 6February 111,659
- 6December 301,659
- 8April 291,706
- 9November 31,720
- 10May 51,732
The seasonal curve of births
Connecting all 366 days reveals deep valleys around New Year and Golden Week, and a peak in September.
See monthly averages as a table
| Month | Avg. daily births / year |
|---|---|
| January | 2,297 |
| February | 2,268 |
| March | 2,237 |
| April | 2,337 |
| May | 2,319 |
| June | 2,355 |
| July | 2,421 |
| August | 2,429 |
| September | 2,469 |
| October | 2,368 |
| November | 2,303 |
| December | 2,270 |
Frequently asked questions
- What is the most common birthday in Japan?
- In Japan's vital statistics (2015-2024), the most common birthday is January 5, with about 2,820 births per year on average.
- What is the rarest birthday in Japan?
- January 1 has the lowest yearly average, at about 1,475 births per year. Counting the total number of people who share a birthday, February 29 - which only exists in leap years - is the smallest group.
- How many Japanese people were born on February 29?
- An estimated 82,000 Japanese people, applying the 2015-2024 birth share to Japan's population. February 29 only exists in leap years (once every four years as a rule), so it is by far the least shared birthday.
About the data
- Source: Ministry of Health, Labour and Welfare, Vital Statistics of Japan (final figures), archived statistical table 7 of the birth volume, “Live births by place, month, day and hour of birth”, downloaded from e-Stat (Vital Statistics) on 2026-08-02. The counts cover births of Japanese nationals in Japan.
- We aggregated the 10 years 2015-2024 (8,549,425 births in total). The ranking uses the average number of births per year for each of the 366 calendar days; days with an identical average share the same rank.
- February 29 exists only in leap years (2016, 2020 and 2024 within the period), so its average is per leap year.
- “Japanese people sharing this birthday” is an estimate: the Japanese population of 119,078,000 (Statistics Bureau of Japan, Population Estimates, final figures as of February 1, 2026) multiplied by each day's share of births in 2015-2024, rounded to the nearest hundred. It assumes the month-day distribution of births is similar across all generations, which is an approximation.
- Only national holidays fixed to a calendar date are noted. Moving holidays (Coming of Age Day, Marine Day, Respect for the Aged Day, Sports Day, and the equinox holidays) are not tied to a single date.
- A clear pattern in the data: fewer births are recorded around the New Year holidays (January 1-3 and December 31) and on national holidays, and more on weekdays around long holidays.