1. When do I have to return it by?

Question

1. When do I have to return it by?

You have to return it by tomorrow/Monday.

2. When is the due date?
The due date is March 3rd.

3. When is the deadline?
The deadline is tomorrow evening.

(Are the questions and answers correct?)

Answer 1

1. When do I have to return it by?

The first is a bit awkward, but OK. The second and third are just fine!