Grading Scale Chart

This grading scale chart is the reference table behind every percentage-to-letter conversion on this site. Find your percentage in the middle column, read across for the letter grade, and read right for the grade points used in GPA math. One caution before you use it: this is the common scale, not a universal law. Schools do vary, and the last section shows how to confirm the scale your course actually uses.

Use the calculator below to convert any score instantly, or scroll for the full chart and the explanations that make it useful.

The common grading scale chart

This is the most widely used US grading scale, with plus and minus grades and the standard 4.0 grade point values:

In the grading scale chart above, note the boundaries that matter most: 90 is the line between A- and B+, 80 between B- and C+, and 70 between C- and D+. Students sitting within a point or two of a boundary should double check their category weights and any unentered scores, because a single assignment can tip the letter.

How to read this grading scale chart

Three columns, three uses. The percentage range column converts a numeric score to a letter: an 88% is a B+ because it falls in 87–89. The letter grade column is what appears on report cards and transcripts. The grade points column feeds GPA calculations: each letter converts to points, points multiply by credits, and the total divides by credits (see how to calculate GPA for the full method).

Two details in the chart deserve attention. First, A+ and A both convert to 4.0 grade points on the standard scale: the plus is honorific, it does not raise your GPA above 4.0 (weighted scales are the exception). Second, the steps between letters are uneven in percentage terms but even in points: B+ (3.3) to B (3.0) is 0.3 points, same as B to B- (2.7), even though the percentage bands differ in width. Internalizing these two facts prevents most conversion errors.

Grading scale chart: plus and minus grades explained

Plus and minus grades split each letter into three bands (except A, which splits into A+ and A, and F, which stands alone). They exist to make grading fairer: without them, an 89% and an 80% both earn a B, which feels wrong to most teachers and students.

For GPA math, each step is worth 0.3 grade points, except the step from A- (3.7) to A (4.0), which is 0.3 as well, and A+ which caps at 4.0 rather than going to 4.3. Memorize the anchor points (A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0) and add or subtract 0.3 for the plus or minus.

Not every school uses plus/minus. Where they are absent, the scale collapses to five letters: A (90–100) = 4.0, B (80–89) = 3.0, C (70–79) = 2.0, D (60–69) = 1.0, F (below 60) = 0. This simpler version cuts both ways: an 89% earns a B worth 3.0 points, while on the plus/minus scale it would be a B+ worth 3.3. But a 90% earns a full A worth 4.0 instead of an A- worth 3.7. Whether the simple scale helps or hurts you depends on where your scores cluster.

Grading scale variations you will actually see

When a grading scale chart differs from the common version above, it is usually one of these:

The 90-80-70 scale (no plus/minus). Common in many high schools and some colleges: 90+ = A, 80+ = B, 70+ = C, 60+ = D, below 60 = F. Simple, but coarse.

Shifted boundaries. Some courses set A at 92 or 94 instead of 90, or pass/fail lines at 70 instead of 60. Science and engineering courses are the most likely to shift cutoffs, and the syllabus always states them.

Graduate and professional scales. Many graduate programs treat anything below a B (or B-) as failing for degree purposes, even though the letter scale looks the same. The chart converts the same way; the stakes differ.

Standards-based grading. A growing number of K-12 schools report 1–4 or "exceeds/meets/approaching" instead of A–F. These systems convert to traditional scales differently by district, so ask your school for its conversion table rather than guessing.

The practical rule: the common chart is your default assumption, and the syllabus is the override. When they conflict, the syllabus wins, always.

How grading scales turn into GPA

The grade points column is the bridge between a grading scale chart and your GPA. Each course's letter becomes points, points multiply by credit hours, and the sum divides by total credits. A quick demonstration with four one-credit courses:

Grades: A- (3.7), B+ (3.3), B (3.0), A (4.0). Total points = 3.7 + 3.3 + 3.0 + 4.0 = 14.0. Divide by 4 courses: 14.0 / 4 = 3.50.

Now the same grades on a no-plus/minus scale: A (4.0), B (3.0), B (3.0), A (4.0). Total = 14.0, GPA = 3.50. Identical here by coincidence of the numbers, but try A-, B+, B+, B on both scales: plus/minus gives (3.7 + 3.3 + 3.3 + 3.0) / 4 = 13.3 / 4 = 3.325, while the simple scale gives (4.0 + 3.0 + 3.0 + 3.0) / 4 = 13.0 / 4 = 3.25. Same performance, different GPA, which is why knowing your school's exact scale matters.

Quick conversions using the grading scale chart

A few read-across examples to build fluency with the chart:

• 95% falls in 93–96, so it is an A, worth 4.0 grade points.
• 88% falls in 87–89, so it is a B+, worth 3.3 grade points.
• 91% falls in 90–92, so it is an A-, worth 3.7 grade points.
• 76% falls in 73–76, so it is a C, worth 2.0 grade points.
• 59% is below 60, so it is an F, worth 0.0 grade points.

One judgment call the chart cannot make for you: rounding. A 89.5% sits exactly on the B+/A- boundary. Some teachers round to the nearest whole number (89.5 becomes 90, an A-), some round down always, and some keep the decimal. Rounding policy is a frequent source of grade disputes, so it is worth one line in the syllabus and one question before finals week.

For teachers: choosing and publishing your scale

If you are building a course, treat the grading scale chart as a design decision, not an afterthought. A plus/minus scale distinguishes student performance more precisely, but it multiplies boundary disputes: with 13 cutoffs instead of 5, more students land near a line. A simple A–F scale is coarser but easier to defend.

Whatever you choose, publish the full chart on the syllabus on day one, including your rounding policy and what happens at exact boundaries. Students cannot aim at a target they cannot see, and a published scale ends most grade arguments before they start. If your department mandates a scale, say so: it reassures students the cutoffs are not personal. Finally, sanity check your scale against your assessments before the term begins. If your exams are brutally hard and the class average lands at 68%, a standard chart will fail half the room, which usually means the assessments or the curve need adjusting, not the students.

Which grading scale does your school use?

Do not guess. Check in this order: (1) the course syllabus, which usually prints the scale on the first page; (2) the student handbook or catalog, which states the institutional scale; (3) the registrar or counseling office, which can confirm how historical grades were recorded. If you transfer schools, ask how the new school converts your old grades: some recalculate everything onto their own scale, which can move your GPA slightly in either direction.

For teachers building a course, the scale choice is a design decision with real consequences. A plus/minus scale rewards students more precisely but creates more boundary disputes. Whatever you choose, publish it on day one: students cannot aim at a target they cannot see.

Grading scale chart: FAQs