---
title: "Happy Pi Day 2025"
author: Cassie Jones
date: "2025-03-14 20:26:20 America/Los_Angeles"
updated: "2025-03-14 23:49:00 America/Los_Angeles"
summary: "Happy Pi Day! Let's discuss the date formats that get you Pi."
---

Happy Pi Day!

It is once again March 14!
In the m/d date format, that's 3/14.
But what about international Pi Day?
Well if you do d/m, you are out of luck, 31/4 doesn't work because April has 30 days.
Luckily for everyone, the best date format is year-month-day anyway.
It's <time datetime="2025-03-14">2025-03-14</time>!

But we're leaving off the year.
Can we get a real Pi Day?
<time datetime="3141">3141-59-26</time> doesn't work, 59 is absolutely not a real month.
We can get our first valid month 31 nonillion years from now, on <time style="word-break: break-all" datetime="31415926535897932384626433832795">31415926535897932384626433832795-02-88</time>[^1], except that months don't have 88 days.
<time style="word-break: break-all" datetime="3141592653589793238462643383279502884197169399375">3141592653589793238462643383279502884197169399375-10-58</time> is also not a valid day.
In fact, you have to wait until <time style="word-break: break-all" datetime="31415926535897932384626433832795028841971693993751058209749445923078164-06-28">31415926535897932384626433832795028841971693993751058209749445923078164-06-28</time> to get a valid Pi Day.

Which is also a Tau Day, coincidentally.
See you in 31 duovigintillion years!

But until then, today I am making apple pie and pizza today.
Have a nice day y'all.

[^1]: I just barely did this one from memory, I had to look the others up.