How to calculate your GPA

Your GPA is simply a credit-weighted average of your grades. Here is the exact method, a full worked example, and how to handle percentages and different grading scales.

By the Calculator Den team · Updated 2026-09-25

Your GPA looks intimidating until you see what it really is: an average of your grades, weighted by how many credits each course was worth. That is the whole idea. A hard four-credit module counts more than a one-credit elective, so you cannot just add your letters and divide. Once you know the four steps, you can work out your grade point average for any semester in a couple of minutes, and you can predict what a given result will do to it. Here is exactly how.

What your GPA actually measures

GPA stands for grade point average. Every grade you earn is converted into a number of grade points, usually on a 4.0 scale where an A is 4, a B is 3, a C is 2, a D is 1 and an F is 0. Your GPA is the average of those grade points across your courses, with each course counting in proportion to its credit hours. So a GPA of 3.5 means that, credit for credit, your grades sit halfway between a B and an A.

The credit weighting is the part people forget, and it is the part that matters most. Two students with the exact same letters can end up with different GPAs if their strong and weak grades fall on courses of different sizes. That is not a quirk, it is the point: the number reflects where you did well relative to how much each course was worth.

The GPA formula in one line

Here is the formula you will use every time:

GPA = (sum of grade points times credit hours for every course) divided by (total credit hours).

Two totals go in. The top is the total quality points, which you get by multiplying each course's grade points by its credits and adding them all up. The bottom is simply all your credit hours added together. Divide the first by the second and you have your GPA. Everything below is just doing that carefully.

How to calculate it by hand, step by step

First, convert every letter grade into its grade points using your school's scale (4.0, 3.0, and so on). Second, multiply each course's grade points by its credit hours to get that course's quality points. Third, add up all the quality points, and separately add up all the credit hours. Fourth, divide total quality points by total credit hours. The result, rounded to two decimals, is your GPA. If you are shaky on the averaging idea underneath it, our post on how to work out a percentage covers the same weighted-average logic in everyday terms.

A full worked example

Say one semester looks like this: English, an A, worth 3 credits; Maths, a B, worth 4 credits; History, a C, worth 3 credits; and a Lab, an A, worth 2 credits. Convert the grades to points on the 4.0 scale: 4, 3, 2 and 4. Now multiply by credits: English 4 times 3 is 12, Maths 3 times 4 is 12, History 2 times 3 is 6, Lab 4 times 2 is 8. Add the quality points: 12 plus 12 plus 6 plus 8 is 38. Add the credits: 3 plus 4 plus 3 plus 2 is 12. Divide: 38 divided by 12 is about 3.17. So the semester GPA is 3.17, a solid B-plus average. Notice how the four-credit B pulled harder than the two-credit A, exactly as the credit weighting intends.

Turning a percentage or a mark into grade points

Plenty of students only have percentages, not letters, and this is where scales differ. Most 4.0-scale systems map roughly like this: 90 to 100 is an A (4.0), 80 to 89 a B (3.0), 70 to 79 a C (2.0), 60 to 69 a D (1.0), and below that an F (0). Convert each percentage to its grade points using that band, then run the same credit-weighted average. The one rule that never changes: use your own institution's official conversion table, because the cut-offs are not universal.

This matters even more outside the United States. Many universities, including some in Botswana and across Africa, run their own scale or map percentages to points differently, and a few use a 5.0 top instead of 4.0. The method is identical, only the conversion table changes. Find your university's grading scale in the student handbook, convert each mark with it, and the formula above does the rest.

Weighted vs unweighted GPA in high school

High schools add one twist. An unweighted GPA treats every class the same, capping at 4.0. A weighted GPA gives harder classes, like Honours, AP or IB, extra points, often up to 5.0, so an A in a tougher class is worth more than an A in a standard one. If your school weights grades, use its weighted table when you convert, and be clear about which number a college is asking for, because the two can differ by half a point or more.

Your cumulative GPA across semesters

Your cumulative GPA is not the average of your semester GPAs. It is the same formula run over every course you have ever taken: total quality points from all semesters, divided by total credits from all semesters. That is why one weak semester early on loosens its grip as you take more credits later, and why a late run of strong grades lifts you more slowly than you might hope. To see how a single upcoming result moves your average before you sit it, the GPA calculator lets you add a planned grade and watch the number shift.

The one mistake almost everyone makes

By far the most common error is ignoring credits and averaging the grade points on their own. In our worked example that would give (4 plus 3 plus 2 plus 4) divided by 4, which is 3.25 rather than the correct 3.17. Small here, but on a full transcript the gap grows, and it always flatters or punishes you unfairly. Always multiply by credits first. If you want the same care applied to a single class rather than a whole semester, our grade calculator and the piece on what grade you need on your final handle that end of it.

Do it in seconds

The maths is simple but fiddly, and one slip on the credit weighting throws the whole number off. The free GPA calculator takes your grades and credit hours, applies the scale, and returns your GPA with the quality points shown, so you can check the working. For the plain-English version of the method, keep our guide on how to calculate GPA open alongside it. Know your number, know what moves it, and you can plan the grades you actually need instead of guessing.