How this instrument works
A test, assignment, or course score is usually recorded as two numbers — points earned and points possible — and the percentage that matters for grading is simply the ratio of the two. That percentage then gets translated into a letter grade using cutoff bands: the most common US convention treats 90% and above as an A, 80-89% as a B, 70-79% as a C, 60-69% as a D, and anything below 60% as an F, though individual schools, districts, and instructors sometimes shift these cutoffs or add plus/minus tiers.
The percentage calculation itself is unaffected by how many total points the assignment was worth — 42.5 out of 50 and 85 out of 100 both reduce to the same 85%, which is exactly why percentage is the standard way to compare scores across assignments of very different point totals. Only after that percentage is computed does the letter-grade lookup happen, checking which of the standard bands the percentage falls into.
Because grading scales vary by institution, this calculator applies the widely-used 90/80/70/60 standard as a reasonable default rather than a universal rule — always check your specific school or instructor's syllabus if you need the letter grade to match an official transcript exactly, since a program with a stricter or looser curve will draw the cutoff lines in different places.
- Enter the points earned on the assignment or test.
- Enter the total points possible.
- Read the resulting percentage.
- Read the letter grade that percentage maps to on the standard 90/80/70/60 scale.
Worked example — 85 points out of a 100-point test
A test scored 85 points earned out of 100 points possible converts directly to 85 ÷ 100 × 100 = 85.0%. On the standard scale, 85% falls in the 80-89% band, so the letter grade is a B.
Compare that to a shorter, 50-point quiz scored 47 out of 50: 47 ÷ 50 × 100 = 94.0%, which crosses into the 90% A band despite being a smaller raw point total — the percentage, not the raw score, is what the letter grade actually tracks.
Questions
What is the standard letter grade cutoff scale?
The most commonly used US convention is A for 90% and above, B for 80-89%, C for 70-79%, D for 60-69%, and F for anything below 60%. It's a widely used default, especially in US public schools, but not universal — some institutions use plus/minus subdivisions (like B+ or C-) or shift the cutoff percentages, so check your specific school's grading policy if you need an exact match.
Why does a 47/50 score outscore an 85/100 score in letter grade?
Because letter grades are assigned from the percentage, not the raw point total — 47 out of 50 is 94%, while 85 out of 100 is 85%, so despite the smaller raw score, the 47/50 result represents a higher proportion of the available points and earns the higher letter grade. Comparing raw scores across assignments worth different point totals is misleading for exactly this reason.
Does this handle plus and minus grades like B+ or C-?
No — this uses the simpler five-tier scale (A, B, C, D, F) without plus/minus subdivisions. Many schools do use finer bands, commonly splitting each letter into a top third (+), middle third, and bottom third (-) of its percentage range; if your school grades that way, use this calculator's percentage output and apply your school's specific plus/minus cutoffs to it.
What happens with a score right at a cutoff, like exactly 90%?
Exactly 90% is treated as meeting the A threshold, since the standard convention is inclusive at the lower bound of each letter band (90% and above is A, not strictly above 90%). Some instructors round scores like 89.5% up to 90% before applying the cutoff and others don't — if a grade is borderline, it's worth checking your specific instructor's rounding policy.
Can points possible be something other than 100?
Yes — the formula works for any point total, since it always converts to a percentage first regardless of whether the assignment was worth 10 points, 50 points, or 237 points. That's the entire purpose of converting to a percentage: to make scores comparable no matter what the original point scale was.