How GPA Is Calculated: Changing Letter Grades to Numbers
You get letter grades in your classes. One class might be an A, another a B. Schools also give you a single number that adds them together. That number is your GPA. GPA means grade point average. It changes each letter grade into a number and then averages those numbers. Not every class is weighted the same. A class with more credit hours has a larger weight. This guide gives the scale, the calculations, and a full example. You can then compute your GPA by hand.
The 4.0 Scale
U.S. schools typically grade on a 4.0 scale. The best possible grade earns 4.0 points, while an F counts as 0.0 points.
The guide and its tool use this GPA scale: A+ = 4.0, A = 4.0, A‑ = 3.7, B+ = 3.3, B = 3.0, B‑ = 2.7, C+ = 2.3, C = 2.0, C‑ = 1.7, D+ = 1.3, D = 1.0, F = 0.0.
Here’s how the scale works. Dropping one step from an A lowers the GPA by a few tenths. An A‑ is 3.7. A B+ is 3.3. A plain B is 3.0.
Note that an A+ and an A are both 4.0 on this scale. There is no bonus above 4.0, so your GPA cannot go above 4.0 on this scale.
Start by converting each letter grade to its point value. Then finish the remaining calculations.
Credit Hours and Why They Matter
Every class lists credit hours. Credit hours roughly indicate how much time the class takes and how important it is. If a class meets more often, it typically has more credit hours.
Grade points depend on credit hours. Instead of adding point values, multiply each grade’s point value by the class’s credit hours. That product is the point total for the class.
This explains why a 4‑credit class moves your GPA more than a 2‑credit class. If you get an A in both, the 4‑credit A gives you 4.0 times 4, which is 16.0 points. The 2‑credit A gives you 4.0 times 2, which is 8.0 points. The first class adds twice as many points.
A low grade pulls your GPA down more in a 4‑credit class than in a 2‑credit one. So give your big‑credit courses top priority.
A Full Worked Example, Step by Step
Let's walk through a full term, one step at a time. You have five classes.
Step 1: Look up the point value for each letter, then multiply by the credits.
English A (3 credits) = 12.0 points. That is 4.0 times 3. Math B (4 credits) = 12.0 points. That is 3.0 times 4. History A- (3 credits) = 11.1 points. That is 3.7 times 3. Science B+ (4 credits) = 13.2 points. That is 3.3 times 4. Art A (2 credits) = 8.0 points. That is 4.0 times 2.
Step 2: Add up all the points. Adding 12.0 and 12.0 gives 24.0. Add 11.1 to reach 35.1. Add 13.2 for a total of 48.3. Finally, add 8.0 to get 56.3.
Step 3: Add up all the credits. 3 plus 4 plus 3 plus 4 plus 2 is 16 credits.
Step 4: Divide the total points by the total credits. GPA = total points ÷ total credits. With 56.3 points over 16 credits, the GPA is 3.52.
The weighting is clear. Science earns the most points even though its grade is a B+; it carries 4 credits. Art has the top grade, an A, but only 2 credits, so it scores the fewest points.
Try a What-If
When you understand the calculation, you can try out different scenarios. Imagine one of your grades is higher—how much would that raise your GPA?
Keep the schedule the same and change only one grade. If the Science grade goes from a B+ to an A, the schedule yields a GPA of 3.69.
Here is why. An A is worth 4.0, and Science has 4 credits. So Science would give you 16.0 points instead of 13.2 points. That is 2.8 more points. Your new total would be 59.1 points over the same 16 credits. 59.1 divided by 16 is 3.69.
The GPA went from 3.52 to 3.69. The jump feels big because Science is a 4-credit class. The same jump in the 2-credit Art class would move your GPA less.
Use what‑if checks to set goals and spot the class that gives the biggest return for your effort. But a what‑if is only a plan—it doesn’t promise a grade. In the end, you still have to earn it.
One Honest Note: Schools Vary
Not all schools do this the same way. Learn the main differences.
Some schools weight honors and AP classes on a 5.0 scale. In that system, a top grade in a hard class can be worth more than 4.0, and a GPA can go above 4.0.
A few schools skip plus and minus grades. They just give A, B, C, D or F, each worth a whole number of points. That keeps the grading system simple.
First, verify your school’s GPA rules. This guide uses the standard scale shown above. The calculator below works with that same scale. If your institution uses a different scale, the GPA you get might vary slightly. The method doesn’t change: multiply each grade point by its credit hours, add all up, then divide by the total credits.
Try it yourself
Try it yourself. Write down each class, the letter grade you received, and its credit hours. Do the calculation by hand once, following the steps above. After that, enter the same numbers into the GPA Calculator on DailyCalcWorks (dailycalcworks.com) to see if your result matches. The calculator does the math for you, so you can see exactly how the GPA is computed.