How to Calculate Your GPA: Letter Grades, the 4.0 Scale, and Weighted vs Unweighted
GPA (grade point average) turns your letter grades into a single number on a 4.0 scale, and it follows you from high school transcripts to college applications. The math is simple once you know the conversion table, but credits and weighting trip a lot of people up.
Step 1: convert letters to grade points
On the standard US 4.0 scale, each letter grade maps to a point value. The most common table, including plus and minus grades, looks like this:
- A / 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, D- = 0.7
- F = 0.0
Some schools skip plus/minus grades entirely, and some cap A+ at 4.0 while others award 4.3. Your school's official table is the one that counts, so check the student handbook if you are unsure.
Step 2: weight by credits and divide
If every class counts equally, GPA is just the average of the grade points. But most transcripts weight by credit hours: multiply each course's grade points by its credits, sum those products (quality points), and divide by total credits.
Worked example: English (3 credits, A = 4.0), Biology (4 credits, B+ = 3.3), History (3 credits, B = 3.0), PE (1 credit, A = 4.0). Quality points: 3 x 4.0 = 12.0, 4 x 3.3 = 13.2, 3 x 3.0 = 9.0, 1 x 4.0 = 4.0, total 38.2. Total credits: 3 + 4 + 3 + 1 = 11. GPA = 38.2 / 11 = 3.47.
Weighted vs unweighted GPA
Unweighted GPA uses the standard 4.0 cap for every class. Weighted GPA gives extra points for harder courses: many high schools add 1.0 for AP or IB classes (so an A is 5.0) and 0.5 for honors (an A is 4.5). That is why you see weighted GPAs above 4.0. Colleges often recalculate GPAs with their own formula, so treat your weighted number as school-specific rather than universal.
Semester GPA vs cumulative GPA
Your semester (or term) GPA covers only the courses from that term. Your cumulative GPA covers everything so far: total quality points from all terms divided by total credits from all terms. Note that a strong semester moves a cumulative GPA less as you accumulate credits. If you have 60 credits at 3.0 (180 quality points) and add a 15-credit semester at 4.0 (60 quality points), your cumulative GPA becomes 240 / 75 = 3.2, not 3.5.
Let the calculator do the bookkeeping
Tracking quality points across terms by hand is where mistakes creep in. GradeBuddy supports US letter grades with GPA out of the box: enter your grades per subject and term and it keeps your averages current, with support for multiple terms and school years. If a big final is coming up, the guide on what you need on your final walks through the exam-target math.
Common questions
- Is a 3.5 GPA good?
- A 3.5 unweighted GPA sits between a B+ and A- average and is generally considered good. Whether it is competitive depends on context: selective colleges often see applicants above 3.8 unweighted, while many programs consider 3.0 and up solid.
- How do I calculate GPA from percentages?
- First convert each percentage to a letter grade using your school's scale (commonly 90-100 = A, 80-89 = B, 70-79 = C, 60-69 = D, below 60 = F), then convert letters to grade points and average. Schools differ, so use your official conversion.
- What is the difference between weighted and unweighted GPA?
- Unweighted GPA caps every class at 4.0. Weighted GPA adds bonus points for advanced courses, typically +1.0 for AP/IB and +0.5 for honors, so it can exceed 4.0. Both usually appear on high school transcripts.
- Does an A+ count as 4.0 or 4.3?
- It depends on the institution. Many high schools and colleges cap A+ at 4.0, while some award 4.3. Check your school's official grading policy, because that is the number on your transcript.