---
title: math.Acos
description: Returns the arccosine, in radians, of the given number.
categories: []
keywords: []
action:
  aliases: []
  related:
    - functions/math/Asin
    - functions/math/Atan
    - functions/math/Atan2
    - functions/math/Pi
    - functions/math/Sin
    - functions/math/Cos
    - functions/math/Tan
  returnType: float64
  signatures: [math.Acos VALUE]
---

{{< new-in 0.130.0 >}}

```go-html-template
{{ math.Acos 1 }} → 0
```