That depends. If the book is available there is no waiting time, you simply download it.
If the book is already out on loan you will be invited to join a waiting list and you will be notified, via email, as soon as the book is available. When you get notified depends on where you are on the waiting list, and when the book is returned.
To find your place on the waitlist for a book on archive.org:
1. Log in and go to the book’s page on archive.org.
2. On the archive.org page, you will see a message above the book preview that indicates your position on the waitlist.
When it is your turn to borrow the book, you will receive an email notifying you.
You will have 48 hours to borrow or it will be passed to the next person on the list.
To find your position on the waiting list in openlibrary.org:
1. Log in and go to the book’s page on openlibrary.org. You can use the Openlibrary_edition link on the archive.org page.
2. On the openlibrary.org page, you will see a number above the Leave waiting list button that indicates your position.
When it is your turn to borrow the book, you will receive an email notifying you.
You will have 48 hours to borrow or it will be passed to the next person on the list.