# Getting started with parameters

[YouTube video](https://www.youtube.com/watch?v=EXtl-dG5mu4)

Parameters let you define a value (for example _material thickness_) in one place and then reference that value throughout your project. When you change the parameter, everywhere where you’re using that parameter automatically updates.

![](https://content.cuttle.xyz/learn/getting-started-with-parameters/0ec132dac0eb6dbbb90f0fc91b612ea1aa9eea27db164023d0c6db71b5eb5cab.gif)

Parameters can reference other parameters and use math expressions. For example:

![](https://cuttle-content.imgix.net/learn/getting-started-with-parameters/d055203233f96cece4b8c13d3d430fe2c5f74ceaf523be7ef90a0f7f05b8bc20.png?auto=compress,format&q=60&fit=max&w=720&h=720&dpr=2)

See [Math Reference](https://cuttle.xyz/learn/parameters/math-reference) and [Vector Reference](https://cuttle.xyz/learn/parameters/vector-reference) for a list of all the operators and functions you can use.

## **Parameter Types**

You can create **project parameters** which are accessible everywhere in your project.

You can also create **component parameters** which are only accessible within the component you create them in. These parameters can then be modified for each instance of the component.

## **Multi-line Expressions**

You can use multiple lines of javascript in an expression. You’ll need to `return` a value.

![](https://cuttle-content.imgix.net/learn/getting-started-with-parameters/c7ad6f746bbd40d7de253d8efa1c20885ca88b18ea0093cf7e3934788996b1b8.png?auto=compress,format&q=60&fit=max&w=720&h=720&dpr=2)

Expressions don’t need to evaluate to a number. You can return any javascript value including arrays, objects, functions, etc.