What is another word for optional?

Here are some words that can be used as synonyms for "optional", depending on the context:

Formal:

* Elective

* Discretionary

* Non-compulsory

* Voluntary

* Permissive

Informal:

* Up to you

* Your choice

* If you want

* Not required

Other options:

* Elective

* Non-mandatory

* Free

* Flexible

* At your discretion

The best word to use will depend on the specific situation and the tone you are trying to convey.