**Calculates the value of the PI number** with our online tool. Just enter the number of decimal places you want to calculate its value (up to 15) and press the calculate button to get how much PI is worth.

Obviously, as soon as **the more decimal places there are, the greater the accuracy** of the result, although in school or university problems, using between 3 and 5 decimal places is usually enough.

## Value of the PI number

The number PI, represented by the Greek letter π, has an amount of **infinite number of decimal places** so it cannot be represented by fractions.

In school we are taught that the number **PI is worth 3.1416** and it's not bad but in reality, we have a huge amount of decimals that make π equal to 3.14159265358979323846...

But since working with so many decimal numbers only complicates the operations and we don't usually need so much precision in the calculations, using the **expression of PI to four decimal places** is usually more than enough.

Don't forget, **the number PI is an irrational number** since it cannot be expressed as a fraction. Since it has an infinite number of decimals that does not follow any particular pattern, it is impossible to express it as a fraction composed of numerator and denominator. For example, 22/7 is equal to 3.142857 but its actual value differs from that of π and therefore, it is not right to treat them as an equality when they are not.

## Where does the PI number come from?

The PI number was discovered by the Egyptians as a constant value which** related the diameter and the perimeter of a circumference**:

π = circumference of a circle / diameter

This relationship means that the perimeter of a circle is 3.1416 times its diameter.

## Letter Pi

The letter Pi belongs to the Greek alphabet and depending on whether it is used in upper or lower case, it can mean one thing or another in different disciplines.

For example, **capital letter Pi** (Π) is used in mathematics for the multiplication of a given amount of numbers.

If we write the letter Pi in lowercase (π) then it can have multiple meanings:

- In mathematics, it honors the constant we have seen, which is 3.141516...
- In pedagogy it is used as a symbol
- In economics, the letter pi is also used for parameters such as profit or inflation.
- In number theory, the function π(x) is used to calculate the number of prime numbers less than or equal to x.

But the letter Pi and its symbol is present in many other sectors.