Your CGPA is the average of all your grade points, weighted by the credit units of each course. Once you know the three steps, you can work it out by hand or check what a calculator gives you.
Step 1: Convert each score to a grade point
Most Nigerian universities convert a course score to a letter, and the letter to points. On the 5.0 scale: A (70 to 100) is 5, B (60 to 69) is 4, C (50 to 59) is 3, D (45 to 49) is 2, E (40 to 44) is 1 and F (0 to 39) is 0. On the 4.0 scale: A is 4, B is 3, C is 2, D (40 to 49) is 1 and F is 0.
Step 2: Work out quality points
Multiply the grade point by the course’s credit units. A 3-unit course with a B on the 5.0 scale gives 3 × 4 = 12 quality points.
Step 3: Divide by total units
Add all quality points, add all credit units, and divide the first by the second.
Worked example (5.0 scale)
| Course | Units | Score | Grade | Points | Quality points |
|---|---|---|---|---|---|
| Course 1 | 3 | 72 | A | 5 | 15 |
| Course 2 | 2 | 64 | B | 4 | 8 |
| Course 3 | 3 | 55 | C | 3 | 9 |
| Course 4 | 2 | 47 | D | 2 | 4 |
| Total | 10 | 36 |
GPA for this semester = 36 ÷ 10 = 3.60, which is a Second Class Upper on the 5.0 scale.
From GPA to CGPA
CGPA covers every semester. Add the quality points and units from all semesters, then divide. If your previous CGPA was 3.80 over 60 units and this semester gives 36 points over 10 units, your new CGPA is (3.80 × 60 + 36) ÷ 70 = 3.77.
Common mistakes
- Averaging semester GPAs instead of weighting by units.
- Using the 4.0 grade points on a 5.0 school, or the other way round.
- Leaving out failed courses when your school counts them.
- Rounding too early. Keep two decimals until the end.
Now see what your result means on the CGPA and class of degree guide, or use the CGPA calculator to do the sums for you.
Frequently asked questions
What is the formula for CGPA?
CGPA = total quality points ÷ total credit units, where quality points for a course are credit units × grade point.
Do carry-over courses count?
Most schools count them when you pass them, and some keep the failed grade in the record. Follow your school’s grading policy.