bdayrank.
pick a day
U.S. birth data · 1994–2014 · 86M+ arrivals

How rare is
your birthday?

We counted every American born across 21 years of records and ranked all 366 days — from the September stampede to the holiday-season ghosts. Find out where yours lands, then challenge a friend.

your birthday

tap your day to reveal its rank

366 days ranked11,174 mean births / dayexplore the full map
Sep 9 is America's busiest birthday — 12,344 arrivals a dayDec 25 is the rarest — just 6,601Jul 7 crashes the all-September top 10 at #7Virgo season runs hottest · Capricorn coolest23 strangers in a room → 50–50 odds two share a birthday86 million babies · 21 years of recordsHospitals dodge the holidays — Christmas sits dead last
Sep 9 is America's busiest birthday — 12,344 arrivals a dayDec 25 is the rarest — just 6,601Jul 7 crashes the all-September top 10 at #7Virgo season runs hottest · Capricorn coolest23 strangers in a room → 50–50 odds two share a birthday86 million babies · 21 years of recordsHospitals dodge the holidays — Christmas sits dead last
00 / The verdict

Your verdict goes here.

Pick your day in the picker above — or tap any cell on the map, any bar on the rank line, any dot on the dial.

366 days are waiting. One of them is yours.

01 / The map

A year of arrivals, at a glance.

Every cell is one day, colored by how many Americans show up. September burns amber. The holidays fade to deep violet. Hover to inspect, tap to select.

rarebusy6,60112,344 births / day
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
* dashed cell = Feb 29, the leapling slotclick any day to load its verdict
02 / The rank line

All 366 days, in single file.

Busiest on the left, rarest on the right. Scroll the line, hover to sniff around, and tap any bar to claim it.

hover the line…
12,344 peakfloor 6,601
03 / Head to head

Whose birthday is rarer?

Add up to four people. Longest bar means the busiest birthday — the shortest one takes the rarity crown.

Select your birthday up top — you'll auto-join the ring — then add a friend or three.

04 / The stars

Which sign owns the nursery?

Average daily births per astrological sign. You are — pick a birthday to find out your sign. Virgo season edges out every other sign, while Capricorn brings up the rear.

Virgo
0
Leo
0
Cancer
0
Libra
0
Gemini
0
Scorpio
0
Taurus
0
Pisces
0
Sagittarius
0
Aquarius
0
Aries
0
Capricorn
0

Virgo is the most common sign (11,783 average daily births), while Capricorn is the least common (10,554). Late-summer conception peaks push Virgo and the signs around it to the top.

06 / The extremes

The hottest — and the coldest — ten.

Nine of the ten busiest birthdays fall in September. Meanwhile the rarest days are almost all holidays — scheduled deliveries and C-sections simply don't land on them.

Most common birthdays
Least common birthdays

average daily U.S. births, 1994–2014

07 / The math

Now ruin a party trick: the odds.

How many people does it take before two of them share a birthday? Fewer than intuition says. Drag the dial and watch the probability collapse the room's uniqueness.

people in the room
23
chance of a match
50.7%
250100

at just 23 people the odds pass 50–50. By 57, it's a 99% near-lock.

the september surge

September is the busiest birth month — count back 40 weeks and you land in the holiday–New-Year window. January is the quietest: it's short, and February conception math keeps it calm.

the holiday ghosting

Hospitals schedule fewer induced labors and C-sections on holidays. Result: Dec 25, Jan 1, Dec 24 and Jul 4 all sit in the rarest five.

the dataset in one line
0Mbirths · 21 years · 366 days · mean 11,174/day

What the data shows

September dominates

Nine of the ten most common birthdays fall in September, roughly nine months after the December holidays.

Holidays are quiet

Christmas, New Year's Day and the Fourth of July sit at the very bottom — scheduled inductions and C-sections avoid them.

Leap day is rarest of all

Feb. 29 only exists every four years, so leap-day babies are the rarest club in the calendar even though the daily average looks ordinary.

Curious how it all works? Read the methodology