A GPA is a credit-weighted average of grade points. To calculate it by hand, convert each letter grade to its point value, multiply that value by the course's credit hours, add the results, and divide by the total credits. This method matters because a four-credit class should influence the result more than a one-credit class. The calculator follows the same process and rounds the final GPA to two decimal places.

1. Convert letter grades to points

Start with the grading scale used by your school. On this calculator's default scale, an A is 4.00, an A- is 3.70, a B+ is 3.30, and a B is 3.00. Other letter grades continue down to an F at 0.00. An A+ is 4.00 by default, but the calculator includes an option to make it 4.33. Use that option only if it matches your school's rules. See the complete GPA scale guide for every letter value.

2. Multiply points by credit hours

For every graded course, multiply its grade points by its credits. The product is sometimes called quality points. A three-credit A produces 12.00 quality points because 4.00 times 3 equals 12.00. A four-credit B+ produces 13.20 because 3.30 times 4 equals 13.20. Keep the products separate until you have handled every course, which makes the arithmetic easier to check.

3. Add the totals and divide

Add all quality points, then add all attempted credits included in the GPA. Divide the quality-point total by the credit total. Do not average the letter-grade values directly when courses have different credit values. A direct average would give every class equal influence and would not represent a credit-weighted GPA.

Worked semester example
Course	Grade	Points	Credits	Quality points
English Composition	A	4.00	3	12.00
Biology with lab	B+	3.30	4	13.20
Calculus I	A-	3.70	3	11.10
Public Speaking	B	3.00	2	6.00
Total			12	42.30

This schedule has 42.30 quality points across 12 credits. Dividing 42.30 by 12 gives 3.53, so the semester GPA is 3.53 after rounding to two decimal places.

Semester GPA and cumulative GPA

A semester GPA uses only courses from one term. A cumulative GPA combines the graded work from multiple terms. You cannot reliably combine two semester GPAs by taking a simple average unless both semesters have exactly the same number of GPA credits. Instead, weight the earlier GPA by its earlier credits, then add the new semester's quality points and credits.

Suppose the student in the example begins with a 3.40 cumulative GPA over 30 credits. The earlier record represents 102.00 quality points. Add the new 42.30 points to get 144.30, and add 12 new credits to get 42. Dividing 144.30 by 42 gives a new cumulative GPA of 3.44 after rounding. In the calculator, enter 3.40 and 30 under the earlier-semesters option to perform this step.

Which courses should you include?

Include courses that your school counts toward GPA and use the credit value shown in its records. Pass/fail courses and withdrawn courses are usually excluded because they generally do not supply letter-grade points, but policies vary. Check your school's policy before leaving them out. Repeated courses, transfer courses, remedial classes, and incomplete grades can also receive different treatment at different schools.

Common calculation mistakes

Frequent errors include forgetting to multiply by credits, counting a withdrawal as an F, using a percentage cutoff from another school, and mixing a weighted prior GPA with an unweighted semester result. Another error is rounding every course product too early. Keep the original point values through the calculation and round only the final quotient. Also confirm whether your transcript treats an A+ as 4.00 or 4.33.

Before trusting a hand calculation, compare its total credits with the credits shown for the same period on your academic record. A mismatch often reveals an omitted course or a class that should not have been counted. Then check the quality-point total one row at a time. This two-part check is more useful than repeatedly dividing the same totals, because it tests the inputs as well as the final arithmetic. If your answer still differs from an official GPA, ask which institutional rule accounts for the difference.

For advanced classes, decide whether you need an unweighted or weighted result before interpreting the answer. Read the weighted versus unweighted GPA guide, check the complete GPA scale, or return to the GPA calculator and enter your own courses.