* Course load: A full-time student typically takes 12-15 credits per semester. At that pace, 42 credits would take 3-3.5 semesters, or roughly 1.5 to 1.75 years.
* Summer courses: Taking summer courses can significantly shorten the time.
* Transfer credits: If you have previously earned college credit elsewhere, those credits can count towards your 42.
* Part-time study: If you're studying part-time, it will naturally take longer.
* Academic year length: The length of the academic year (number of weeks in a semester) varies between institutions.
In short, there's no single answer. A reasonable estimate is 1.5 to 2 years for a full-time student, but it could be shorter or longer depending on the factors listed above.