To calculate your high school GPA, you assign a number to each letter grade, multiply by the credits each course is worth, add up all those numbers, then divide by your total credits. The standard scale runs from 4.0 for an A down to 0.0 for an F. Once you understand that basic formula, you can calculate both an unweighted and weighted GPA in a few minutes with nothing more than your transcript and a calculator.
The 4.0 Grade Scale
Every GPA calculation starts by converting your letter grades into point values. On the standard unweighted scale used by most high schools:
- A (90–100): 4.0
- B (80–89): 3.0
- C (70–79): 2.0
- D (66–69): 1.0
- F (below 65): 0.0
Some schools also use plus and minus grades, which land between the whole numbers. An A- converts to 3.7, a B+ to 3.3, a B- to 2.7, and so on in increments of roughly 0.3. If your school reports percentage grades instead of letters, you can still map them onto this scale. A 94%, for instance, falls in the A range and converts to a 4.0, while an 85% sits in the B range at 3.0 (or 3.3 if your school recognizes a B+ for the 83–86 range).
Calculating an Unweighted GPA
The simplest version assumes every class counts equally. Here’s the process step by step:
- Step 1: List every course you’ve completed and the letter grade you earned.
- Step 2: Convert each letter grade to its point value using the 4.0 scale above.
- Step 3: Add up all the point values.
- Step 4: Divide that total by the number of classes.
Say you took five classes in a semester and earned an A, A, B, B, and C. That’s 4.0 + 4.0 + 3.0 + 3.0 + 2.0 = 16.0. Divide 16.0 by 5 classes and your GPA is 3.2.
This simple average works when all your courses carry the same number of credits, which is common if every class meets for the same amount of time each week. But if your courses have different credit values, you’ll need the weighted-by-credits method described below.
When Courses Have Different Credits
Some high schools assign more credits to certain classes. A lab science might be worth 1.5 credits while a standard elective is worth 1.0. When credit values differ, a straight average won’t reflect your grades accurately because the higher-credit courses should count more.
The formula is: GPA = total quality points ÷ total credits attempted. Quality points for a single course equal the grade’s point value multiplied by the number of credits that course is worth.
Here’s an example with four courses:
- English (1 credit), grade A: 4.0 × 1 = 4.0 quality points
- Chemistry (1.5 credits), grade B: 3.0 × 1.5 = 4.5 quality points
- History (1 credit), grade A: 4.0 × 1 = 4.0 quality points
- Art (0.5 credits), grade C: 2.0 × 0.5 = 1.0 quality points
Total quality points: 4.0 + 4.5 + 4.0 + 1.0 = 13.5. Total credits: 1 + 1.5 + 1 + 0.5 = 4.0. GPA: 13.5 ÷ 4.0 = 3.375. Notice how the chemistry grade pulls more weight than the art grade because chemistry is worth three times as many credits.
How a Weighted GPA Works
An unweighted GPA caps at 4.0 no matter how challenging your schedule is. A weighted GPA gives you extra points for harder courses, so colleges can see the difference between an A in a regular class and an A in an AP or IB course.
The most common system adds a full point for AP and IB classes and, at many schools, a half point or full point for Honors courses. On this scale, an A in AP Biology is worth 5.0 instead of 4.0, and a B+ is worth 4.3 instead of 3.3. Honors courses typically get the same one-point bump, so an A in Honors French also counts as 5.0.
To calculate a weighted GPA, follow the same steps as before, but use the boosted point values for any AP, IB, or Honors courses. Everything else stays the same: multiply by credits, add it all up, and divide by total credits. Because of the extra points, weighted GPAs can climb above 4.0. A student taking several AP classes and earning mostly A’s might end up with a 4.5 or higher.
Not every school uses the same weighting system. Some add only 0.5 points for Honors and a full point for AP/IB. Others cap the weighted scale at 5.0. Check your school’s student handbook or ask your guidance counselor which system your transcript reflects.
Cumulative GPA Across Multiple Years
Your cumulative GPA includes every graded course from freshman year through wherever you currently stand. The math is identical to the credit-weighted formula, just applied across all semesters at once.
Pull out your transcript and list every course, its credit value, and the grade you earned. Convert grades to point values (boosted values if you’re calculating weighted), multiply each by credits, sum up the quality points, and divide by total credits. That single number is your cumulative GPA.
If you only have your GPA and credit totals for each individual semester or year, you can still combine them. Multiply each semester’s GPA by its credit total to get quality points for that period, add up quality points across all semesters, then divide by the grand total of credits. For example, if you earned a 3.5 over 12 credits in fall and a 3.8 over 14 credits in spring, that’s (3.5 × 12) + (3.8 × 14) = 42 + 53.2 = 95.2 quality points over 26 credits, giving you a cumulative GPA of 3.66.
Quick Percentage-to-GPA Conversion
If your school uses a 100-point percentage scale rather than letter grades, here’s a more granular conversion:
- 93–100: 4.0
- 90–92: 3.7
- 87–89: 3.3
- 83–86: 3.0
- 80–82: 2.7
- 77–79: 2.3
- 73–76: 2.0
- 70–72: 1.7
- 67–69: 1.3
- 65–66: 1.0
- Below 65: 0.0
This table follows the scale published by several colleges, though your school may draw the cutoffs slightly differently. Use your school’s official scale if one is printed on your transcript or report card.
Which GPA Colleges Actually See
When you apply to college, admissions offices typically receive your official transcript, which lists your school’s calculated GPA. Some colleges recalculate it using their own scale, stripping out non-core electives or adjusting the weighting for AP and Honors courses. That means the number you calculate at home might not match exactly what a college uses, but it will be very close and is the best tool you have for tracking your own progress.
Knowing how to run the calculation yourself lets you set grade targets for each semester. If you’re heading into junior year with a 3.4 and want to reach 3.6 by graduation, you can plug in hypothetical grades and credit loads to see exactly what it takes to get there.