When are you leaving? When do you leave?

[Chloe]

Hello all!

Could you tell me whether there is any difference between these both questions. When should I use the first question and when the second one?

Thank you!!!

With best wishes,
Chloe

[Igel]

Hello.

You use the second form if it is something stationary which will happen in the future.
For example:

The bus arrives at 7.15.
When does the bus arrive?

That's an appointment, so you use the Present Simple.

The first form is used if the expression is something planned which will happen in the future.
For example:

I am going to my friend in two hours.
When are you going to your friend?

In your case, the first form is the right one.