How we calculate
Every formula, scale and assumption our calculators use, in one place, so you can check any result against your own gradebook.
Last updated
Grading scale
Letter grades use the standard U.S. plus/minus scale below. A percentage earns a letter once it reaches that letter's minimum, with no rounding: 89.99% is a B+. Grade points use the unweighted 4.0 scale with A+ capped at 4.0.
| Letter | Percentage | GPA (4.0) |
|---|---|---|
| A+ | 97–100% | 4.0 |
| A | 93–96% | 4.0 |
| A- | 90–92% | 3.7 |
| B+ | 87–89% | 3.3 |
| B | 83–86% | 3.0 |
| B- | 80–82% | 2.7 |
| C+ | 77–79% | 2.3 |
| C | 73–76% | 2.0 |
| C- | 70–72% | 1.7 |
| D+ | 67–69% | 1.3 |
| D | 63–66% | 1.0 |
| D- | 60–62% | 0.7 |
| F | Below 60% | 0.0 |
Grade inputs
Grade fields accept three formats:
- Percentages:
92or92%, used as is (values above 100 for extra credit are allowed). - Points:
45/50or45 out of 50, converted to earned ÷ possible × 100. - Letters: converted to a typical percentage for that letter: A+ 98, A 95, A- 91, B+ 88, B 85, B- 81, C+ 78, C 75, C- 71, D+ 68, D 65, D- 61, F 50. Use exact percentages when you have them.
Formulas
Class grade (weighted)
Grade = Σ(grade × weight) ÷ Σ(weight)
Dividing by the entered weight, not by 100, gives your current grade when part of the course isn't graded yet. Rows with a grade but no weight are left out (and flagged) whenever other rows are weighted. With no weights at all, every row counts equally.
Needed on the remaining work
Needed = (Target × 100 − Current × completed weight) ÷ remaining weight
Final exam
Needed on final = (Target − Current × (1 − w)) ÷ w
Results are labeled Locked in at 0% or below, and Not reachable above 100%.
Category-weighted grade
Scores inside each category are averaged equally, then the category averages are weighted. Empty categories are skipped.
Test grade
Grade = (Total − Wrong) ÷ Total × 100
GPA
GPA = Σ(grade points × credits) ÷ Σ(credits)
Weighted high school GPA adds +0.5 for Honors and +1.0 for AP/IB/dual enrollment to each passing grade. F grades never receive a bonus.
Cumulative and target GPA
Cumulative = (GPA₁ × C₁ + GPA₂ × C₂) ÷ (C₁ + C₂)
Needed GPA = (Target × (C + N) − Current × C) ÷ N
Known differences from school gradebooks
- Rounding: some teachers round 89.5 to 90; we don't.
- A+: a few colleges award 4.33; we use 4.0.
- Weighting: some high schools use different bonuses or weight only certain courses.
- Special policies: dropped lowest scores, grade floors (minimum 50%), and grade replacement aren't applied automatically.
Your school's official records always take precedence. See our disclaimer.
Testing and review
The calculation code is covered by automated unit tests that run on every change, including edge cases like empty rows, weights over 100% and impossible targets. Worked examples in our articles are re-checked whenever content is updated. Spotted a mistake? Tell us and we'll fix it.