packer/website/content/docs/templates/hcl_templates/functions/numeric/log.mdx

---
page_title: log function reference
description: The `log` function returns the logarithm of a given number in a given base.
---

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> [!IMPORTANT]  
> **Documentation Update:** Product documentation previously located in `/website` has moved to the [`hashicorp/web-unified-docs`](https://github.com/hashicorp/web-unified-docs) repository, where all product documentation is now centralized. Please make contributions directly to `web-unified-docs`, since changes to `/website` in this repository will not appear on developer.hashicorp.com.
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# `log` Function

`log` returns the logarithm of a given number in a given base.

```hcl
log(number, base)
```

## Examples

```shell-session
> log(50, 10)
1.6989700043360185
> log(16, 2)
4
```

`log` and `ceil` can be used together to find the minimum number of binary
digits required to represent a given number of distinct values:

```shell-session
> ceil(log(15, 2))
4
> ceil(log(16, 2))
4
> ceil(log(17, 2))
5
```