* Type of degrees: Switching from a Bachelor's to a Master's typically takes 1-2 years (full-time). A second Bachelor's degree might take the same, or even longer if there's significant overlap in coursework. A doctoral degree (PhD, EdD, etc.) after a Master's can take 4-7 years or more.
* Prior coursework: If your previous degree has relevant coursework, you might be able to transfer credits, shortening the time needed for a second degree.
* Program intensity: A full-time program will be much faster than a part-time program.
* University policies: Each university has its own rules regarding credit transfers and program length.
In short, there's no single answer. It could be as short as a year or as long as seven years or more, depending on the circumstances.