Why are credits part of the formula at all?

Because courses aren't equal. A 4-credit lab science represents roughly four times the scheduled work of a 1-credit seminar, so its grade carries four times the weight in your average. Ignoring credits would let small electives cancel out your core courses.

How do I calculate GPA when grades are percentages?

Convert each percentage to a letter using your school's bands (see the scale chart), then follow the same steps. Converting the average percentage instead gives a different, usually wrong, answer — convert per course.

How does retaking a course affect the calculation?

It depends on your school's policy: grade replacement (only the new grade counts), averaging (both attempts count), or both grades shown with only the first counted. The calculator can't know your policy — check your academic handbook.

How to Calculate GPA — Formula, Steps & Worked Example

GPA = total quality points ÷ total credits, where quality points are each course's grade points multiplied by its credits. That one sentence is the whole system; the rest of this page is working it carefully, with examples.

Step 1 — Convert each grade to points

Use the standard 4.0 scale: 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 · F 0.0. The full chart, with percentage equivalents, is on the GPA scale chart page.

Step 2 — Multiply each course's points by its credits

These products are called quality points. A 4.0 in a 4-credit course earns 16.0 quality points; the same grade in a 1-credit course earns 4.0. This is where weighting enters — bigger courses move the average more.

Step 3 — Add up quality points and credits separately

Keep two running totals: total quality points, and total credits attempted (including credits for any F — an F earns 0 points but its credits still count in the next step, which is exactly why failures sting).

Step 4 — Divide

GPA = total quality points ÷ total credits. Worked example: A in a 3-credit course (12.0), B+ in a 4-credit course (13.2), A- in a 3-credit course (11.1) — totals 36.3 quality points over 10 credits, so GPA = 36.3 ÷ 10 = 3.63. Try it in the GPA calculator, which starts with exactly these rows.

Step 5 — Blend terms for a cumulative GPA

Do not average your semester GPAs unless the terms had equal credits. Instead, carry the two totals forward: add every term's quality points, add every term's credits, divide once. If you only know your previous GPA and credits, the equivalent blend is (previous GPA × previous credits + new quality points) ÷ total credits — the cumulative calculator does this for you.

Weighted GPA (high school)

Weighted GPA adds a level bonus to the points in Step 1 before multiplying: +1.0 for AP/IB, +0.5 for Honors, capped at 5.0 per class. Everything after that is identical. See the high school calculator for both figures side by side.

Common mistakes

Averaging the letter points without credits. Fine only when every course has identical credits.
Averaging percentages, then converting. Convert each course first; the two methods give different answers.
Forgetting the F's credits. Zero points, full credits in the denominator.
Assuming every school uses this scale. Some cap an A+ at 4.0, some award 4.3, some skip plus/minus entirely. For anything official, your institution's scale wins.

How to Calculate GPA — the formula, step by step