# \pi

The π symbol (Greek small letter pi, U+03C0), written as \pi in LaTeX math mode.

https://texform.dev/latex/symbols/pi

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Greek letters](https://texform.dev/latex/topics/greek) |
| Packages | base |
| Allowed mode | math |
| Glyph | π |
| Unicode | U+03C0 GREEK SMALL LETTER PI |
| Delimiter | No |

## Syntax

```latex
\pi
```

Takes no arguments.

## Common tasks

### How to write pi

```latex
\pi
```

[Open in Playground](https://play.texform.dev/?input=%5Cpi)

### How to write a circle area

```latex
A=\pi r^2
```

[Open in Playground](https://play.texform.dev/?input=A%3D%5Cpi+r%5E2)

### How to write a product of primes with pi

The number is \pi; a product operator is \prod.

```latex
\prod_{p\le x}\bigl(1-\tfrac{1}{p}\bigr)
```

[Open in Playground](https://play.texform.dev/?input=%5Cprod_%7Bp%5Cle+x%7D%5Cbigl%281-%5Ctfrac%7B1%7D%7Bp%7D%5Cbigr%29)

## Usage frequency

8.61% of formulas in the measured corpus contain this entry, rank 6 of 474 entries with frequency data.

## In TeXForm

TeXForm parses this entry as a character leaf mapped to U+03C0 (GREEK SMALL LETTER PI).