Hidden in π

Birthdays

Is your October birthday in π?

Every day of October is in there. Pick the way you write dates, then tap your birthday.

Write dates as
  • The earliest October birthday in π is 21/10, at decimal place 173.
  • The last to turn up is 31/10, at decimal place 32,727.
  • 17 of the 31 days turn up as a full birthday (DD/MM/YYYY, any year from 1950 to 2025) in the first million decimals.

Tap a day to see its full birthdays, every year from 1950 to 2025.

Every month

§ 3

Your number is in π.*

We looked. All 100 billion digits. Twice, for luck.

A phone number, a birthday like 14/03/1999, a word, or up to four words like i love you. We won't tell anyone what you type. * Probably. 99.995% of ten-digit numbers. The other 0.005% are being difficult.

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