How to calculate your GPA and CGPA (5.0 scale, with a worked example)
By Eduvora · Updated 12 October 2026
Your GPA is a single number that summarises how well you did in a semester. Your CGPA does the same for your whole programme so far. The arithmetic is simple once you know the three ingredients.
The three ingredients
Credit units show how much weight a course carries. A 3-unit course counts for more than a 2-unit course. Grade points convert a letter grade into a number. Quality points are the two multiplied together.
On the 5.0 scale used by many Nigerian universities, the grade points are:
| Grade | Grade point |
|---|---|
| A | 5 |
| B | 4 |
| C | 3 |
| D | 2 |
| E | 1 |
| F | 0 |
Some schools use a slightly different table, for example without an E, so confirm with your school's handbook before relying on any calculator.
The formulas
- Quality points for a course = credit units × grade point
- GPA = total quality points ÷ total credit units (for one semester)
- CGPA = total quality points ÷ total credit units (for all semesters so far)
Worked example: one semester
Suppose you took six courses in your first semester:
| Course | Units | Grade | Grade point | Quality points |
|---|---|---|---|---|
| Course 1 | 3 | A | 5 | 3 × 5 = 15 |
| Course 2 | 3 | B | 4 | 3 × 4 = 12 |
| Course 3 | 3 | C | 3 | 3 × 3 = 9 |
| Course 4 | 2 | A | 5 | 2 × 5 = 10 |
| Course 5 | 4 | B | 4 | 4 × 4 = 16 |
| Course 6 | 2 | D | 2 | 2 × 2 = 4 |
| Total | 17 | 66 |
Total units: 3 + 3 + 3 + 2 + 4 + 2 = 17. Total quality points: 15 + 12 + 9 + 10 + 16 + 4 = 66.
GPA = 66 ÷ 17 = 3.88 (to two decimal places).
Worked example: moving to CGPA
In the second semester you take courses worth 20 units and earn 62 quality points. Your second-semester GPA is 62 ÷ 20 = 3.10.
Now combine both semesters:
- Total units: 17 + 20 = 37
- Total quality points: 66 + 62 = 128
- CGPA = 128 ÷ 37 = 3.46
A common mistake: averaging GPAs
It is tempting to add 3.88 and 3.10 and divide by two. That gives 3.49, which is wrong. The second semester had more units, so it should count for more. Always work from total quality points and total units, never from averaged GPAs.
What about failed and repeated courses?
An F gives 0 grade points, but its credit units still count in the total units, so it lowers your GPA. Rules for resits and carryovers differ between universities, so check how your school records a repeated course.
Checking your work
- Write every course with its units and grade.
- Multiply units by grade point for each course.
- Add the quality points, then add the units.
- Divide, and round only at the end.
Your official GPA is whatever your school's records show. Use this method to plan and to understand your standing, and to spot mistakes early. To see which class of degree a CGPA falls into, read our guide on grades and degree classes in Nigerian universities.