Each course, depending on the course itself is between 2 and 4 credit hours. Most are 3 credit hours. If you use an average of 3 it would be about 35 courses. If you had two semesters a year and took 8 courses per semester it would take about 2 years to finish. You could shorten the time by taking summer courses though.
Normally, one credit hour is equivalent to 50 minutes in class. If a class is 3 credit hours and meets three times a week, it will mean that you spend 1.5 hours per day. If you want to go full time, you may need to take 12 credits hours per semester.