Problem Calculating GPA

[deanhystad]

As iberdeen says, your loop is not looping through user_grades and converting them to number grades. Instead you are looking up the highest grade every time through the loop. Essentially this:

for grade in grades:
    Did anyone get an A+?
        total += 4
    Did anyone get an A?
        total += 4
    Did anyone get an A-?
        total += 3.7
    ...

When you should be doing:

for grade in grades:
    if grade == A+?
        total += 4
    else if grade == A?
        total += 4
    else if grade == A-?
        total += 3.7
    ...

Does the assignment require you to use two loops? One will do.

Output:
grades = []
while True:
    letter_grade = input("Enter a grade: ('q' to end.)").upper()
    if letter_grade == "Q":
        break
    elif letter_grade in ("A+", "A"):
        grades.append(4)
    elif letter_grade == "A-":
        grades.append(3.7)
    ....

average = sum(grades) / len(grades)

Finally, using a bunch of if statements is not "pythonic". I would use a dictionary lookup. I would make a dictionary that converts letter grades to number grades:

letter_grades = {
    "A+": 4, "A": 4, "A-": 3.7, "B+": 3.3, "B": 3, "B-": 2.7,
    "C+": 2.3, "C": 2, "C-": 1.7, "D+": 1.3, "D": 1, "F": 0
}

Then the conversion is simple and short:

number_grade = letter_grades[user_input]

My program to take in letter grades and compute an average is 17 lines long with input checking and nice formatting. Your if statement is 23 lines long.