---
title: ES|QL TAU function
description: 
url: https://www.elastic.co/elastic/docs-builder/docs/3016/reference/query-languages/esql/functions-operators/math-functions/tau
products:
  - Elasticsearch
---

# ES|QL TAU function
## Syntax

![Embedded](https://www.elastic.co/elastic/docs-builder/docs/3016/reference/query-languages/esql/images/functions/tau.svg)


## Parameters


## Description

Returns the [ratio](https://tauday.com/tau-manifesto) of a circle’s circumference to its radius.

## Supported types


| result |
|--------|
| double |


## Example

```esql
ROW TAU()
```


| TAU():double      |
|-------------------|
| 6.283185307179586 |