---
page_title: upper function reference
description: >-
  The `upper` function converts all lowercase letters in the given string to
  uppercase.
---

# `upper` Function

`upper` converts all cased letters in the given string to uppercase.

## Examples

```shell-session
> upper("hello")
HELLO
> upper("алло!")
АЛЛО!
```

This function uses Unicode's definition of letters and of upper- and lowercase.

## Related Functions

- [`lower`](/packer/docs/templates/hcl_templates/functions/string/lower) converts letters in a string to _lowercase_.
- [`title`](/packer/docs/templates/hcl_templates/functions/string/title) converts the first letter of each word in a string to uppercase.