---
title: ES|QL ACOSH function
description: 
url: https://www.elastic.co/elastic/docs-builder/docs/3028/reference/query-languages/esql/functions-operators/math-functions/acosh
products:
  - Elasticsearch
---

# ES|QL ACOSH function
## Syntax

![Embedded](https://www.elastic.co/elastic/docs-builder/docs/3028/reference/query-languages/esql/images/functions/acosh.svg)


## Parameters

<definitions>
  <definition term="number">
    Number greater than or equal to 1. If `null`, the function returns `null`.
  </definition>
</definitions>


## Description

Returns the [inverse hyperbolic cosine](https://en.wikipedia.org/wiki/Inverse_trigonometric_functions) of a number.

## Supported types


| number        | result |
|---------------|--------|
| double        | double |
| integer       | double |
| long          | double |
| unsigned_long | double |


## Example

```esql
ROW a=1.8
| EVAL acosh=ACOSH(a)
```


| a:double | acosh:double       |
|----------|--------------------|
| 1.8      | 1.1929107309930491 |