Pi (π) is an irrational number, meaning its digits do not repeat in a recurring pattern. The digits of pi extend infinitely without end. With an infinite number of digits, it would take an infinite amount of time to say all the digits of pi aloud. However, we can estimate how long it would take to say a certain number of pi’s digits.

## How Many Digits of Pi Are Known?

As of 2023, pi has been calculated to over 70 trillion digits. The current world record holder for calculating pi is Timothy Mullican, who computed pi to over 62.8 trillion digits in 2020. However, for most practical purposes, only about 40 digits of pi are needed to perform calculations requiring high precision.

## How Quickly Can a Person Speak Digits?

The average English speaking person speaks at a rate of about 150 words per minute. Since each digit counts as a “word”, that equates to roughly 150 digits per minute. However, reciting long strings of numbers is more mentally taxing than normal speech. A reasonable estimate is that someone could accurately recite pi at around 100 digits per minute on average.

## How Long to Recite 1 Million Digits of Pi?

If someone could recite pi at 100 digits per minute, it would take them approximately:

Total digits | 1,000,000 |

Digits per minute | 100 |

Total minutes | 1,000,000 / 100 = 10,000 |

Total hours | 10,000 / 60 ≈ 166 hours |

Total days | 166 / 24 ≈ 7 days |

So at a pace of 100 digits per minute, it would take around 7 days of continuous reciting to make it through 1 million digits of pi.

## How Long for 1 Billion Digits?

For 1 billion digits (1,000,000,000 digits):

Total digits | 1,000,000,000 |

Digits per minute | 100 |

Total minutes | 1,000,000,000 / 100 = 10,000,000 |

Total hours | 10,000,000 / 60 ≈ 166,667 hours |

Total days | 166,667 / 24 ≈ 6,944 days |

That’s over 19 years of continuously speaking digits of pi!

## How Long for 1 Trillion Digits?

Extending this further, reciting 1 trillion digits would take:

Total digits | 1,000,000,000,000 |

Digits per minute | 100 |

Total minutes | 1,000,000,000,000 / 100 = 10,000,000,000 |

Total hours | 10,000,000,000 / 60 ≈ 166,666,667 hours |

Total days | 166,666,667 / 24 ≈ 6,944,444 days |

Total years | 6,944,444 / 365 ≈ 19,027 years |

That’s over 19,000 years nonstop! Clearly reciting that many digits of pi would not be possible for a single human lifetime.

## How Long for the Current Record of 70 Trillion Digits?

As mentioned earlier, the current record for calculating pi is around 70 trillion digits. Here’s how long it would take to recite that many digits:

Total digits | 70,000,000,000,000 |

Digits per minute | 100 |

Total minutes | 70,000,000,000,000 / 100 = 700,000,000,000 |

Total hours | 700,000,000,000 / 60 ≈ 11,666,666,667 hours |

Total days | 11,666,666,667 / 24 ≈ 485,277,778 days |

Total years | 485,277,778 / 365 ≈ 1,329,178 years |

That’s over 1.3 million years! Clearly no single person could recite all 70 trillion+ digits in their lifetime.

## How Long Would It Take a Group?

While it’s impossible for one person to recite all the known digits of pi, what if we had a large group working together? Here’s an estimate:

- 70 trillion digits total
- 365 digits per person per day (reciting for 8 hours at 100 digits per minute, with breaks)
- 70 trillion / 365 ≈ 192 million person-days
- With 1000 people reciting, it would take 192,000 days
- 192,000 days / 365 days per year ≈ 526 years

So if we had 1000 people reciting pi digits for 8 hours per day, it would take over 500 years for the group to get through all 70 trillion digits calculated so far. A large university math department working together could perhaps achieve this feat!

## Conclusions

Some key conclusions:

- It’s impossible for a single person to recite all digits of pi due to its infinite nature.
- Even just 1 trillion digits would take over 19,000 years for one person.
- The current record of 70 trillion digits would take over 1.3 million years!
- With a large enough group, it’s conceivable to recite 70 trillion digits in about 500 years.
- For all practical purposes, 40 digits of pi are sufficient for most calculations.

While we can’t say all of pi, calculating more and more digits provides insight into the nature of mathematics. Pi continues to fascinate both mathematicians and non-mathematicians alike!

### Additional Questions

Here are some additional questions that readers may have about reciting digits of pi:

#### What is the longest anyone has recited pi from memory?

The Guinness World Record for reciting the most decimal places of pi from memory is held by Rajveer Meena, who recited 70,000 digits in March 2015. It took him nearly 10 hours to accomplish this feat!

#### Can memorizing long strings of digits damage your brain?

There is no evidence that memorizing many digits of pi causes permanent damage to the brain. However, the intense focus and mental effort needed to memorize tens of thousands of digits can certainly be mentally draining. People who take on these challenges need good concentration skills and the ability to keep their mind engaged for hours on end.

#### Why do people attempt to memorize and recite pi?

For some, memorizing many digits of pi is a way to challenge oneself mentally and test the brain’s information storage capacity. Others enjoy the recognition that comes with breaking pi memorization records. It can also be satisfying to master memorizing something as complex and infinite as pi. Some find the repetitive nature of memorizing digits to have a calming, meditative effect as well.

#### Do techniques exist for memorizing long strings of digits?

Yes, there are various techniques and memory aids that can help when memorizing long strings of numbers. Two common tactics are:

**Chunking**– Breaking long numbers into more manageable chunks of 2-5 digits you can remember as units**Mnemonics**– Associating number chunks with words, people, places or objects to create memorable connections

With practice, these methods allow people to memorize hundreds or even thousands of digits through meaningful associations rather than just raw memorization.

### Fun Facts About Pi

Here are some interesting and fun facts about the number pi that readers may find entertaining:

- Pi is an irrational number, meaning its digits go on forever without repeating in a pattern.
- Pi is transcendental, so it can’t be the root of any polynomial with rational coefficients.
- Ancient civilizations estimated pi at 3 or 25/8. Archimedes narrowed it down to between 3 1/7 and 3 10/71 in 250 BC.
- March 14th (3/14) is celebrated as Pi Day because the date resembles pi (3.14).
- Albert Einstein was born on Pi Day – March 14, 1879.
- Pi appears in equations describing many fundamental principles of physics, like the ideal gas law, Faraday’s law, and Einstein field equations.
- “Piphilology” is the practice of memorizing large numbers of pi’s digits for fun.
- In 1995, Hiroyoki Gotu memorized 42,195 digits of pi and is considered the “father of modern pi recitation.”
- The record for reciting pi from memory belongs to Rajveer Meena of India, who recited 70,000 digits over 10 hours in 2015.

While reciting all its digits is impossible, pi continues to fascinate and motivate new mathematical insights that contribute to human knowledge.

## References

Here are sources that were used and consulted in researching this article on reciting digits of pi:

- http://www.piday.org/million/ – Pi Day Million Digits Page
- https://www.guinnessworldrecords.com/world-records/most-pi-places-memorised – Pi Memorization Guinness World Record
- https://en.wikipedia.org/wiki/Chronology_of_computation_of_%CF%80 – Wikipedia on Calculation of Pi Digits Through History
- https://www.exploratorium.edu/pi/pi-history – The Exploratorium’s Overview of Pi History
- https://www.piday.org/fun-facts/ – Additional Facts About Pi from the Pi Day Website