Pi Day is March 14th (3/14), just as Pi is “3.14.”  However, many non-U.S. countries represent dates by day-month, making this date 14/3. The date of 3/14 is “American Pi (Day).” Pi is often represented as 22/7 (the fraction), and this would be July 22nd (an International Pi Day).
   
“Pi Day is each March 14 (3.14), while Pi Approximation Day is July 22 (roughly equal to 22/7” was posted on Twitter by dege13 on March 2, 2009. “We don’t recognise today as PI day. It’s an American PI day because they follow mm/dd/yy. We celebrate it on 22/7 - 22nd July” was posted on Twitter by Swami Gulagulaananda on March 14, 2010. “UK Pi day is 22/7 - which is more accurate than American Pi day, which is just 3.14 ... but not as ammusingly named….” was posted on Twitter by Lucas R Black on March 14, 2010. “22/7 is Pi day 14/3 is American Pi day” was posted on Twitter by Porygon Seizure on March 13, 2020. “International Pi Day is 22/7, which is a better approximation than American Pi Day 😊” was posted on Twitter by MJW on March 16, 2021.
   
“Isnt a better choice (approximation 😉 ) of Pi day 22/7 than 3/14 ?? Strange ! Thoughts? #PiDay #22JulyforPiDay” was posted on Twitter by Bharath Ananthasubramaniam on March 15, 2018. “I don’t understand why 14/3 is Pi Day. Isn’t 22/7 a better choice?” was posted on Reddit—Dadjokes on March 14, 2022.
 
     
Wikipedia: Pi
The number π ( /paɪ/; spelled out as “pi” ) is a mathematical constant, approximately equal to 3.14159. It is defined in Euclidean geometry[a] as the ratio of a circle’s circumference to its diameter, and also has various equivalent definitions. It appears in many formulas in all areas of mathematics and physics.
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In the United States, Pi Day falls on 14 March (written 3/14 in the US style), and is popular among students.
 
Twitter
dege13
@dege13
@oliviamunn “Pi Day is each March 14 (3.14), while Pi Approximation Day is July 22 (roughly equal to 22/7). http://tinyurl.com/Pi-day
8:59 AM · Mar 3, 2009·Twitter Web Client
     
Twitter
Swami Gulagulaananda
@Gulagulaananda
@amoolyatatti We don’t recognise today as PI day. It’s an American PI day because they follow mm/dd/yy. We celebrate it on 22/7 - 22nd July
6:16 AM · Mar 14, 2010·Twitter Web Client
   
Twitter
Lucas R Black
@LucasBlack
UK Pi day is 22/7 - which is more accurate than American Pi day, which is just 3.14 ... but not as ammusingly named….
5:58 PM · Mar 14, 2010·Echofon
   
Twitter
Brightly Striped Policy Institute 🥴🥳
@crk5
For those of you who are excited about American Pi day today, just a reminder that the 22nd July (22/7) is officially Pi day in Australia 😊
9:31 PM · Mar 13, 2013·TweetDeck
   
Twitter
Geoff Dallimore
@PatentUK
It’s not “pi day”, it’s “American pi day”. The rest of the world have to wait until 22/7 for “pi approximation day”.
6:40 PM · Mar 14, 2015·Twitter Web Client
   
Twitter
Mike Dickison
@adzebill
Hey NZ, yesterday was 3/14 in America: Pi Day. Did you miss it? (Miss American Pi Day?) Don’t worry, we get Approximate Pi Day on 22/7.
2:18 PM · Mar 14, 2016·Twitter for iPhone
     
Twitter
Bharath Ananthasubramaniam
@bharath_ananth
Isnt a better choice (approximation 😉 ) of Pi day 22/7 than 3/14 ?? Strange ! Thoughts? #PiDay #22JulyforPiDay
4:20 AM · Mar 15, 2018·Twitter Web Client
 
Twitter
Dave Vanness
@djvanness
Replying to @JohnMullahy
I tend to think of 3/14 as American Pi day and 22/7 as European Pi Day.
7:52 AM · Mar 14, 2019·Twitter Web App
     
Twitter
Porygon Seizure
@porygon_seizure
Replying to @felix_croc
22/7 is Pi day
14/3 is American Pi day
11:23 PM · Mar 13, 2020·Twitter Web Client
 
Twitter
MJW
@the_lazyknight
Replying to @ThePracticalDev
International Pi Day is 22/7, which is a better approximation than American Pi Day 😊
2:39 PM · Mar 16, 2021·Twitter Web App
 
Reddit—Dadjokes
Posted by u/coffee-and-chess March 14, 2022
I don’t understand why 14/3 is Pi Day.
Isn’t 22/7 a better choice?
 
Twitter
‘jokes’ of a guy 😂
@the_alphaman_
I don’t understand why 14/3 is Pi Day.
Isn’t 22/7 a better choice?
#humour
2:00 AM · Mar 15, 2022·Kipruto