๐ How Rare Is My Birthday? Check Your Day (2026)
๐ 10 Rarest Birthdays in the US
| Rank | Date | Avg Births/Year | Why Rare? |
|---|---|---|---|
| #1 | Feb 29 | ~1,000* | Leap Day โ only every 4 years |
| #2 | Dec 25 | 6,574 | Christmas Day |
| #3 | Jan 1 | 7,792 | New Year's Day |
| #4 | Dec 24 | 8,069 | Christmas Eve |
| #5 | Jul 4 | 8,796 | Independence Day |
| #6 | Jan 2 | 9,307 | Day after New Year's |
| #7 | Dec 26 | 9,543 | Day after Christmas |
| #8 | Nov 27 | 9,718 | Near Thanksgiving |
| #9 | Nov 23 | 9,883 | Near Thanksgiving |
| #10 | Oct 31 | 9,978 | Halloween |
* Feb 29 births averaged across all years including non-leap years. Source: CDC/FiveThirtyEight data 1994โ2014.
๐ฅ 10 Most Common Birthdays in the US
| Rank | Date | Avg Births/Year | Why Common? |
|---|---|---|---|
| #1 | Sep 9 | 12,301 | Peak holiday conception |
| #2 | Sep 19 | 12,229 | December conception window |
| #3 | Sep 12 | 12,209 | December conception window |
| #4 | Sep 17 | 12,148 | Holiday season + cold weather |
| #5 | Sep 10 | 12,143 | Holiday season + cold weather |
| #6 | Jul 7 | 12,113 | Post-July 4th scheduling |
| #7 | Sep 20 | 12,100 | December conception window |
| #8 | Sep 15 | 12,082 | December conception window |
| #9 | Sep 16 | 12,064 | December conception window |
| #10 | Sep 18 | 12,055 | December conception window |
๐งฌ Why Are Some Birthdays Rarer Than Others?
Birthday rarity isn't random โ it's driven by three main factors that explain why certain dates consistently see fewer births year after year.
Scheduled procedures: About 1 in 3 US births are via C-section, which is typically a planned surgery. Doctors rarely schedule procedures on holidays or weekends, creating artificial dips on dates like Christmas, New Year's, and Thanksgiving. This is the single biggest factor in birthday rarity.
Conception timing: The holiday season (NovemberโDecember) sees higher conception rates due to colder weather, more indoor time, and holiday togetherness. This creates the September birth peak. Conversely, spring conceptions are lower, making winter births less common.
Cultural and superstitious factors: In some cultures, certain dates are considered unlucky. April 1 (April Fool's Day) is the least common birthday in some countries. September 11 saw a noticeable dip in US births after 2001.
๐ Birth Month Popularity Ranking (US)
โญ Fun Birthday Facts
Explore More Rarity Tools
โ Birthday Rarity FAQ
What is the rarest birthday?
February 29 (Leap Day) is the rarest, occurring only once every 4 years. Among non-leap days, December 25 (Christmas) is the rarest because doctors avoid scheduling births on major holidays.
What is the most common birthday?
September 9 is the most common birthday in the US. Nine of the top ten most common birthdays fall in September, corresponding to holiday season conceptions in December.
How many people share my birthday?
On average, about 22.5 million people worldwide share any given birthday. Use our calculator above for a more specific estimate based on your actual date.
Why are September birthdays so common?
September births correspond to December conceptions. The holiday season, cold weather, and more indoor couple time increase conception rates. Male fertility may also peak in colder months.
Does my birthday affect my personality?
While no scientific evidence links birth date to personality, your birthday determines your zodiac sign. Try our Birth Chart Calculator to discover your full astrological profile.