*Learn how GPA is computed.*
Lets say you take 32 credits one year: for 13 of those credits you get A, for 10 you get B, and the remaining 9 credits are C. First, use the fact that every credit of A is worth 4 points, B is 3 points, and C is 2 points. Next, multiply each grade point by the number of credits, and then add them up:
4(13) + 3(10) + 2(9) = 100
Finally, divide this number by the total number of credits: 100/32 = 3.125. So your GPA for that year is 3.125
To figure out what grades you need to keep your GPA at a certain level, let's use another example. Suppose you have 52 credits of C's, 28 credits of B's, and 30 credits of A's (total credits = 110). Your current GPA is 2.8, and you want to know how many credits of A's needed to bring your GPA up to a 3.0.
Set up the following equation, where x is the number of extra credits you are going to take and make A's:
(2.8)(110) + 4x = (3.0)(110 + x)
To break it down, it's (current GPA)(current # credtits) + (4 points for A's)(# extra credits) = (desired GPA)(total # credits).
When you solve for x, you get x = 22. So you need to earn 22 more credits worth of A's to bring your GPA up to a 3.0
Here's another example. Suppose you have taken 80 credits and your current GPA is 3.75. You want to know how many credits of B's it would take to bring your GPA down to a 3.5. We use the same equation as above:
(3.75)(80) + 3x = (3.5)(80 + x)
When you solve for x, you get x = 40. So if you take 40 more credits and get all B's (or half A's and half C's), your GPA would drop to 3.5.
Using the same example as above, how many credits of C would it take to bring your GPA down to a 3.5?
(3.75)(80) + 2x = (3.5)(80 + x)
x = 13.333. If you get earned 13 credits of C, your GPA would be 3.505, and if you earned 14 credits of C, your GPA would be 3.489.
Use this formula whenever you need to make GPA computations.