About the Pi Digit Generator
Pi is the ratio of a circle's circumference to its diameter, about 3.14159, and its decimal digits never end or repeat. This tool calculates the digits of pi on the spot, up to 5,000 places after the decimal point, and shows them in tidy groups of ten so you can read or memorise them. You can also type a number, such as a date or phone number, and see where it first appears in the first 5,000 decimals. Nothing is looked up from a table, because the digits are computed with an exact integer formula inside your browser.
Updated October 2026
How to use the Pi Digit Generator
- 1Enter how many digits after the decimal point you want, from 0 to 5,000.
- 2Read the digits, which are grouped in tens after the 3.
- 3Press Copy digits to take the plain, ungrouped digits to your clipboard.
- 4Optionally type a number to search for, such as 1409 for a date, and read where it first appears.
How many digits do you need?
Three decimals (3.141) are enough for most school problems, and 3.14159 suits engineering sketches. Fifteen digits already measure the circumference of the Earth to less than a millimetre. Beyond that, extra digits are for fun and testing, such as memorising a hundred digits or comparing the output of two programs.
Memory and reading tips
- Digits are grouped in tens so that you can chunk them, which is the way memory champions learn long sequences.
- The Feynman point is a run of six 9s starting at the 762nd decimal place.
- To compare with another source, use the Copy digits button and check them side by side.
- Pi day is on 14 March, because 3/14 matches the first digits 3.14.
Using pi in calculations
Pi appears in the circumference of a circle (2 times pi times the radius) and its area (pi times the radius squared). Use the Circle Calculator for those, the Surface Area Calculator for spheres, cylinders and cones, and the Trigonometry Calculator for angles measured in radians. If you need to round a long result to a sensible number of digits, the Rounding Calculator does it exactly.
Features
- Up to 5,000 decimal places
- Digits grouped in tens for easy reading
- Copy as one unbroken string
- Search for any number up to 12 digits
- Digits are calculated, not looked up
- Exact: digits are cut off, not rounded
- Runs in your browser
Frequently asked questions
What are the first digits of pi?
Pi starts 3.14159265358979323846264338327950288. Rounded to two decimal places it is 3.14, and many people use the fraction 22 over 7 as a rough stand-in, which is 3.142857 and correct only to two decimals.
Does pi ever end or repeat?
No. Pi is an irrational number, so its decimal digits go on forever without settling into a repeating pattern. It is also transcendental, which means it cannot be the solution of any ordinary polynomial equation with whole-number coefficients.
How are the digits calculated?
The tool uses Machin's formula, which expresses pi as four times four times the arctangent of one fifth, minus the arctangent of one over 239. Both arctangents are summed as a long series using big-integer arithmetic, with a few extra guard digits so the final digits are right.
Are the digits rounded or cut off?
They are cut off, which is called truncation. Asking for 5 decimals gives 3.14159 even though the next digit, 2, would not change a rounded value. Asking for 6 gives 3.141592 and the next digit would have been 6, so a rounded value would end in 3.141593.
Can I find my birthday in pi?
Type the digits of your date in the search box, for example 1409 for 14 September. The tool shows the first decimal place where that run of digits appears in the first 5,000 decimals. Short numbers usually turn up quickly, while longer ones may not occur until far later than 5,000.
Why would I need so many digits of pi?
Almost nothing practical needs more than about 15 digits. NASA uses around 15 or 16 for interplanetary navigation. Long strings of pi are mainly for memory challenges, programming tests, curiosity and checking that software handles precision correctly.