birthday traffic

How common is a September 17 birthday?

Published by Birthday Traffic Β· Β· Sources and method

September 17

Top 10 most common

Very common

More common than 99.2%of other birthday dates.

1 in 335births in this sample share your birthday.

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  • 12,201births in an average year21 years observed
  • 109%of a typical day11,175 births on an average day
  • #1 of 12September as a month11,811 births per day
  • +6.0%share of births, then to nowfirst five vs last five observed years

September 17 is the 4th most common birthday of the 366 dates in this collection, and the 363rd rarest. It records 256,231 births out of 85,712,738, so roughly 1 in 335 people in this sample were born on it.

It is more common than 99.2% of the other 365 dates and rarer than 0.8%. It records 109.2% of an average day’s count in the sample.

September 17 among all 366 dates

All 366 dates sorted from most to least common by recorded U.S. births 1994–2014, coloured by rarity tier, with September 17 marked.

September 17 among all 366 datesAll 366 dates sorted from most to least common by recorded U.S. births 1994–2014, coloured by rarity tier, with September 17 marked.0100,000200,000300,000Very common: 91 dates, ranks #1–#91Very commonCommon: 92 dates, ranks #92–#183CommonUncommon: 147 dates, ranks #184–#330UncommonRare: 18 dates, ranks #331–#348Very rare: 15 dates, ranks #349–#363Super rare: 3 dates, ranks #364–#366#4 September 17: 256,231September 17 Β· #4 of 366most commonleast common
Very common 91Common 92Uncommon 147Rare 18Very rare 15Super rare 3All 366 dates from most to least common, coloured by the six rarity tiers; September 17 is marked. Recorded U.S. births, 1994–2014.

September 17 against the days around it

Recorded U.S. births, September window, 1994–2014
DateTotal birthsRank of 366
September 14250,282#25
September 15254,652#8
September 16254,393#9
September 17 (this date)256,231#4
September 18254,350#10
September 19257,981#2
September 20255,392#6

September as a whole records 11,811 births per day, ranked #1 of 12 months. Month ranking Β· September 16 Β· September 18

Has September 17 changed over time?

Annual U.S. birth totals changed across this window, so a raw daily count moves with the size of the year. The chart uses each year's share of that year's births instead, in births per 100,000. Averaged over the first five observed years it is 292.9 per 100,000; over the last five, 310.5 per 100,000 (+6.0%).

September 17 as a share of each year’s U.S. births, 1994–2014

Births on September 17 per 100,000 births in that year, one point per year, with the change of source at 2000 marked and the first-five and last-five year means drawn as bands.

September 17 as a share of each year’s U.S. births, 1994–2014Births on September 17 per 100,000 births in that year, one point per year, with the change of source at 2000 marked and the first-five and last-five year means drawn as bands.150200250300350400SSA file from 2000first five: 292.9last five: 310.519941996199820002002200420062008201020122014per 100,000, 1994: 247.4 per 100,000per 100,000, 1995: 224.6 per 100,000per 100,000, 1996: 335.7 per 100,000per 100,000, 1997: 329.6 per 100,000per 100,000, 1998: 327.4 per 100,000per 100,000, 1999: 331.9 per 100,000per 100,000, 2000: 209.2 per 100,000per 100,000, 2001: 308.1 per 100,000per 100,000, 2002: 347.4 per 100,000per 100,000, 2003: 336.7 per 100,000per 100,000, 2004: 324.3 per 100,000per 100,000, 2005: 224.6 per 100,000per 100,000, 2006: 200.7 per 100,000per 100,000, 2007: 315.0 per 100,000per 100,000, 2008: 332.1 per 100,000per 100,000, 2009: 336.3 per 100,000per 100,000, 2010: 335.4 per 100,000per 100,000, 2011: 219.4 per 100,000per 100,000, 2012: 323.9 per 100,000per 100,000, 2013: 340.8 per 100,000per 100,000, 2014: 332.6 per 100,000per 100,000
The dotted line marks the change from the CDC/NCHS file to the SSA file.
September 17 as a share of that year's U.S. births
YearBirths on this datePer 100,000 births
19949,779247.4
19958,757224.6
199613,063335.7
199712,793329.6
199812,905327.4
199913,142331.9
20008,683209.2
200112,664308.1
200214,241347.4
200314,018336.7
200413,577324.3
20059,459224.6
20068,701200.7
200713,798315.0
200814,316332.1
200914,095336.3
201013,605335.4
20118,792219.4
201212,960323.9
201313,542340.8
201413,341332.6

Source break: 1994–1999 counts come from the CDC/NCHS daily file and 2000–2014 from the Social Security Administration daily file. The overlapping years 2000–2003 are taken from the SSA file only, so each year is counted once. But the step at 2000 is a change of source as well as a change of year, and any comparison across it includes that change.

The weekday the date fell on, scheduling practice and recording practice are all inside these lines.

A generation earlier, in the separate daily file for 1969–1988, September 17 ranked #5 of 366 with 10,563 births per occurrence. The 1969–1988 calendar and what changed since.

September 17 in five countries

Countries are compared only over the matched years 2007–2014, which all five sources cover completely, and using births per occurrence so that leap day is handled the same way everywhere. Each country's records are counted on their own.

September 17 rank and intensity, 2007–2014
CountryRank of 366Index (100 = average day)
United States#2115.9
England & Wales#8107.7
Denmark#37107.2
Metropolitan France#3109.7
Malaysia#10108.7

In the matched window the U.S. rank is #2; over the full 1994–2014 collection it is #4. The two numbers answer different questions and usually differ for two reasons at once: the window is eight years against twenty-one, and the metric is births per occurrence against the total across the whole period. Every figure on this page names its window and its metric. Full five-country study.

Among the 6,025,603 people living in Denmark on January 1, 2026, 17,058 have this birthday, one resident in 353. A count of people living there, wherever they were born. How many people in Denmark share a birthday.

Born on September 17

12 people from the English Wikipedia β€œOn this day” birth lists, oldest first. A reading list. Every birth figure on this page comes from the national records.

Names and descriptions from English Wikipedia, CC BY-SA 4.0, retrieved 2026-09-11; curated arts/science/sport entries, years 1800–2008. not a celebrity census. conflicting identities excluded.

Keep going

Open the September 17 card β†’

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.

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