February 28 occurs every year and sits near the middle of the historical U.S. birthday ranking. It ranks #197 out of 366 dates by total recorded births from 1994 through 2014, where rank #1 means most common. The files contain 233,125 February 28 births.
Its share is 0.272%, or about 1 in 368 recorded births. February 28 and February 29 have very different total-birth ranks because they occur different numbers of times.
February 28, beside other birthdays
Average recorded births each time a date occurred, 1994 through 2014.
- Commonness rank
- 197 / 366
- Share of recorded births
- 0.272 %
- Recorded births
- 233,125
Bars start at zero. Rank 1 means most common and uses total births across all 366 dates. The bars use births per actual occurrence; February 29 appeared five times, while the other dates appeared 21 times.
Check February 28 and compare with a friend →February 28 has a birthday date every year
The baseline covers 21 actual February 28 dates, compared with 5 February 29 dates. February 28 averages 11,101.2 recorded births per occurrence; February 29 averages 10,512.2. The chart above uses these occurrence-based averages, while the table below ranks total births.
| Date | Recorded births | Commonness rank | Birth share |
|---|---|---|---|
| February 21 | 232,134 | 212 | 0.271% |
| February 27 | 228,866 | 288 | 0.267% |
| February 28 | 233,125 | 197 | 0.272% |
| February 29 | 52,561 | 366 | 0.061% |
| March 1 | 234,495 | 176 | 0.274% |
| March 2 | 227,660 | 308 | 0.266% |
February 28 ranks #6 within February. See every date in the February guide or the separate leap-day birthday guide for questions about February 29 anniversaries.
NASA's Gregorian calendar explanation sets out the leap-year rule: years divisible by four are leap years. Century years are an exception; they must also be divisible by 400. In common years, March 1 immediately follows February 28; in leap years, February 29 comes between them. A common year has no February 29 observation to count as zero births.
What changes in leap years?
For this comparison, we use SSA U.S. records from 2000 through 2014. That window contains 4 leap years (2000, 2004, 2008, 2012) and 11 common years. Each subgroup compares its dates with nearby dates on the same weekday in those years.
| Calendar group | Years | Occurrences | Births per occurrence | Control mean | Difference |
|---|---|---|---|---|---|
| February 28 in leap years | 2000, 2004, 2008, 2012 | 4 | 11,456.3 | 11,457.4 | -0.0% |
| February 28 in common years | 2001, 2002, 2003, 2005, 2006, 2007, 2009, 2010, 2011, 2013, 2014 | 11 | 11,372.9 | 11,665.6 | -2.5% |
| March 1 in leap years | 2000, 2004, 2008, 2012 | 4 | 11,510 | 11,232.8 | +2.5% |
| March 1 in common years | 2001, 2002, 2003, 2005, 2006, 2007, 2009, 2010, 2011, 2013, 2014 | 11 | 11,423.5 | 11,384.9 | +0.3% |
| February 29 (leap years only) | 2000, 2004, 2008, 2012 | 4 | 10,467.3 | 11,405.8 | -8.2% |
February 28 is almost level with its nearby comparison in the leap-year group. In common years, its difference is -2.5%. March 1 is slightly above its own comparison in both groups, while actual February 29 dates are below theirs. Each row has its own target date, years and control means; the rows should not be combined into one birth total.
These counts do not show whether deliveries moved from one date to another. The leap-year group is small, and its dates have a different mix of weekdays from the common-year group.
The year-by-year February 28 comparison
For each February 28, we consider dates one and two weeks before and after it, within the same calendar year. We exclude actual and standard observed federal holidays using the OPM holiday calendar rules, plus Christmas Eve, December 26 and the Friday after Thanksgiving. Here, February 21 is excluded when it is Washington's Birthday, leaving 57 eligible controls.
| Year | Weekday | Recorded births | Nearby mean | Difference |
|---|---|---|---|---|
| 2000 | Monday | 11,455 | 11,561.3 | -0.9% |
| 2001 | Wednesday | 12,209 | 12,653 | -3.5% |
| 2002 | Thursday | 12,370 | 12,638.5 | -2.1% |
| 2003 | Friday | 12,533 | 12,753.3 | -1.7% |
| 2004 | Saturday | 8,488 | 8,588.8 | -1.2% |
| 2005 | Monday | 11,678 | 12,091 | -3.4% |
| 2006 | Tuesday | 13,223 | 13,416 | -1.4% |
| 2007 | Wednesday | 13,366 | 13,487 | -0.9% |
| 2008 | Thursday | 13,674 | 13,507.5 | +1.2% |
| 2009 | Saturday | 8,396 | 8,532.5 | -1.6% |
| 2010 | Sunday | 6,895 | 7,018.3 | -1.8% |
| 2011 | Monday | 11,160 | 11,625.3 | -4.0% |
| 2012 | Tuesday | 12,208 | 12,172 | +0.3% |
| 2013 | Thursday | 11,601 | 12,017.5 | -3.5% |
| 2014 | Friday | 11,671 | 12,089.5 | -3.5% |
Across all 15 years, February 28's pooled difference is -1.9%; it is below its nearby mean in 13 years. The one-week sensitivity is -0.9%, and the two-week sensitivity is -2.7%. Both keep all target years. We average eligible controls within each year, then compare summed target births with summed annual means. The analysis download supplies exact control dates and exclusions, including the March 1 and February 29 comparisons.
Sources and what these odds mean
The FiveThirtyEight files supply CDC/NCHS births for 1994 through 1999 and SSA births for 2000 through 2014. We exclude overlapping CDC years; annual comparisons use SSA alone. These are historical U.S. records, not a count of living birthday twins or births worldwide.
February 28's birth share divides its recorded count by all 85,712,738 births in the baseline. Its daily average divides that count by the number of actual February 28 dates. Those denominators answer different questions.
Read the methodology for rank and share definitions, see the rarest-birthday guide for February 29's total-based rarity, or use the birthday checker to compare your date.