What is the most common birth month?
Pass this on
September is the most common birth month, at 11,811 births per day. January is the least common, at 10,721 per day, about 9.2% lower.
Months are ranked by births per day. A 31-day month would otherwise beat February on length alone.
- Septembermost common birth month11,811 births per day
- Januaryleast common birth month10,721 births per day
- 9.2%gap between top and bottomper day, month length removed
- 8.7%of all births fall in September7,440,659 recorded
U.S. births per day by month, 1994–2014, in calendar order
Twelve columns, January to December, recorded births per day, with the average day drawn as a line.
- September #1
- August #2
- July #3
- June #4
- October #5
- May #6
- December #7
- February #8
- March #9
- November #10
- April #11
- January #12
| Month | Births per day | Share of all births | |
|---|---|---|---|
| September | 11,811 | 8.7% | |
| August | 11,712 | 8.9% | |
| July | 11,563 | 8.8% | |
| June | 11,306 | 8.3% | |
| October | 11,204 | 8.5% | |
| May | 11,022 | 8.4% | |
| December | 10,991 | 8.3% | |
| February | 10,981 | 7.6% | |
| March | 10,979 | 8.3% | |
| November | 10,927 | 8.0% | |
| April | 10,874 | 8.0% | |
| January | 10,721 | 8.1% |
Check how rare your own birthday is →
The shape of the year
Births rise through the summer, peak in the second week of September and bottom out in winter. In calendar order the pattern is one wave:
| Month | Births per day | Rank | |
|---|---|---|---|
| January | 10,721 | #12 | |
| February | 10,981 | #8 | |
| March | 10,979 | #9 | |
| April | 10,874 | #11 | |
| May | 11,022 | #6 | |
| June | 11,306 | #4 | |
| July | 11,563 | #3 | |
| August | 11,712 | #2 | |
| September | 11,811 | #1 | |
| October | 11,204 | #5 | |
| November | 10,927 | #10 | |
| December | 10,991 | #7 |
This is one country over one 21-year window. The seasonal peak moves between countries: compare five countries over a matched period. Two more countries publish by month rather than by day, which is the same question at a coarser grain: births by month in Canada and birthdays in India.
Related
The most common single date · The least common date · Browse all 366 dates
Sources, method and limits
Main ranking: 85,712,738 recorded U.S. births on 7,670 calendar dates, 1994–2014. CDC/NCHS daily counts for 1994–1999 and Social Security Administration daily counts for 2000–2014, as compiled by FiveThirtyEight and attributed under CC BY 4.0. The overlapping years 2000–2003 are counted once.
Ranks compare totals across the 366 observed month-and-day dates. February 29 occurred 5 times in this window; every other date occurred 21 times, so per-occurrence figures are used wherever seasonality is compared.
Every figure above comes from the administrative records named here, at the granularity those records publish: a day, a month or a year. Coverage and definitions differ between countries and eras, so two sources are combined only where their documentation states the windows are separate, and the page where that happens says so.
Full method, leap-day treatment and definitions.
Want the data? Ask for it.