Built-in Functions

Hands-on: Try the Perform Dynamic Operations with Functions tutorial on HashiCorp Learn.

The Terraform language includes a number of built-in functions that you can call from within expressions to transform and combine values. The general syntax for function calls is a function name followed by comma-separated arguments in parentheses:

max(5, 12, 9)

For more details on syntax, see Function Calls in the Expressions section.

The Terraform language does not support user-defined functions, and so only the functions built in to the language are available for use. The navigation for this section includes a list of all of the available built-in functions.

You can experiment with the behavior of Terraform's built-in functions from the Terraform expression console, by running the terraform console command:

> max(5, 12, 9)
12

The examples in the documentation for each function use console output to illustrate the result of calling the function with different parameters.