Percentage to Letter Grade

Schools map percentage scores to letter grades with local cutoffs — common US defaults are A ≥ 90%, B ≥ 80%, C ≥ 70%, D ≥ 60%, F below 60. Honors weighting and plus/minus grades are not included here.

Edit the cutoff fields to match your syllabus. If your instructor uses 94/84/74/64 or a different scale, enter those thresholds instead of the defaults.

Example: score 87% with cutoffs 90/80/70/60 → letter B. Score 69% → D. Always confirm against your course policy.

There is no national grading scale in the US, which is why the same percentage can be two different letters. The familiar 90/80/70/60 bands are only the most common convention; many courses use 94/84/74/64, some districts run 93/86/79/70, and a few use seven-point bands where anything at or above 93 is an A. Always enter your syllabus values rather than trusting a default.

Cutoffs are usually inclusive at the boundary, so a 90.0 is an A when the A band starts at 90. The ambiguity lies just underneath: whether 89.6 becomes an A depends entirely on whether your instructor rounds to the nearest whole number before applying the bands. Ask rather than assume, because the two policies differ by a full letter at the edge.

Plus and minus grades sit inside these bands and are not produced here. Where they are used, an A band typically splits with A− from 90 to 92.9 and A from 93 to 96.9, and those sub-bands carry different grade points — 3.7 against 4.0 — so a plus/minus school needs the finer thresholds before any GPA calculation.

Portals can disagree with the syllabus, and the syllabus wins. Canvas, PowerSchool, and similar systems apply whatever scheme was configured for the course, may weight categories differently from the printed policy, and often display a running total that excludes ungraded work. Treat the portal letter as provisional until the final grade posts.

Converting a percentage to a letter is only the first step if a curve is involved. Some instructors curve raw scores before mapping, others adjust the cutoffs downward after seeing the distribution, and the two approaches produce different letters for the same raw score — so confirm which one applies before comparing with classmates.

Instructors sometimes publish custom rubrics mid-semester — if cutoffs change, re-enter the updated thresholds rather than assuming the defaults on this form match your syllabus.

Borderline scores near a cutoff deserve a manual check — rounding to one decimal may flip the letter if your instructor uses strict inequality rules.