Formulas and sources
Each formula this calculator uses, where it comes from, and what it leaves out. "How it works" shows the same formula with your own numbers.
Current weighted grade
Simple mode
- Grade
- your current grade, in percent
- G
- an assignment's grade, in percent
- W
- that assignment's weight, in percent
Only rows with a grade and a weight above zero count, each up to 1,000. The grade is worked out over the weight entered so far, so the weights need not total 100%. Final Goal mode starts from this same grade.
Source: Standard formula; no single publisher. It is the weighted mean, the same one the Weighted Mean Calculator works out.
Score needed on the final
Final Goal mode
- Needed
- the score to get on the final, in percent
- Target
- the course grade you want, in percent
- W
- the weight of each graded row, in percent; ΣW is their total
- Final Weight
- the final's weight, in percent
- Grade
- the current grade from the formula above
Above 100%, the target is out of reach with these weights. Below 0%, it is already met; exactly 0% reads Achievable. Work not yet graded and not listed is left out, and the graded work plus the final can total at most 100%.
Source: Standard formula; no single publisher. It solves the weighted mean after the final, (Grade × ΣW + Needed × Final Weight) ÷ (ΣW + Final Weight) = Target, for the one unknown score.
Letter grade
Simple and Final Goal modes
- A+
- 97% and up
- A
- 93% to under 97%
- A-
- 90% to under 93%
- B+
- 87% to under 90%
- B
- 83% to under 87%
- B-
- 80% to under 83%
- C+
- 77% to under 80%
- C
- 73% to under 77%
- C-
- 70% to under 73%
- D+
- 67% to under 70%
- D
- 60% to under 67%
- F
- below 60%
Each letter starts exactly at its percentage, so 89.99% is a B+. The Grade Distribution card groups the letters into A, B, C, D and F at 90%, 80%, 70% and 60%.
Source: The A, B, C and D starting points (90, 80, 70 and 60) are the conversion NCES uses for high school transcripts [1]. The plus and minus steps are widely used; no primary source found (searched NCES and three school catalogs, whose scales differ). Quinnipiac uses the same steps from A to C- [2]; the University of the Incarnate Word has no C- and counts D as 63 to 66 [3].
Sources
- National Center for Education Statistics (NCES), US Department of Education. How is Grade Point Average Calculated?, NAEP High School Transcript Study, "Number Grade Conversion". Last updated April 7, 2011.
- Quinnipiac University. Grading System, Scale of Grades. Academic Catalog, 2026-2027 Edition.
- University of the Incarnate Word, Registrar. Grading Scale. Page marked 2025, read October 5, 2026.
What this calculator does not cover
- It works out one course's grade at a time from the scores and weights you enter. For your standing across courses, see the GPA Calculator.
- It does not drop a lowest score, apply a curve, or count extra credit differently, and its plus/minus letter scale may not be the one your school uses.
Sources checked on .