Birthday Rarity Ranking
Birthday Rarity of May 15
A common birthday- By number of births
- 116/ 366
- By rarity
- 251/ 366
- Average births per year
- 2,417
- Japanese people sharing it (est.)
- 336,600
That is 3.3% more than the all-day average (about 2,340 births/year).
Compared with neighboring days
Across the year
The most and least common days
In the 2015-2024 data, January 5 has the highest yearly average (about 2,820 births/year) and January 1 the lowest (about 1,475).
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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.