There are lots of ways you could ask, and that's one of them:
- Will it take long?
- Will it take a long time?
- Will it take a long time to finish?
- When do you think it'll be done?
- When do you think it might be done?
- Could you tell me when you think it might be done?
- Do you have any idea how long it might take?
How do you ask how long something takes?
Both “how long” and “how much time” are used to ask about the amount of time something takes or has taken.
What is the professional way to ask for time?
If the time works for you, I would like to meet at [time] on [date] at [place]. Please confirm whether that works for you or if another time and place is better. I look forward to our meeting.