Your report card says 88%, the transcript says B+, the GPA line says 3.3, and a friend abroad asks whether that's "a 2:1." Four labels, one performance — and no one ever explained how they connect. Here's the takeaway up front: a grading scale is just a lookup table that turns a raw score into a label. Percentage in, letter out; letter in, GPA point out. Once you can read the table, every one of those numbers stops being mysterious. This guide lays out the typical scales, works a full conversion by hand, and shows you where the traps are — then you can convert your own marks with the free grade conversion tool instead of hunting for a chart.
One rule sits over everything below: scales vary by school, board, and country. Every band here is the typical setup for illustration. Your institution publishes the numbers that actually count — check its policy before you treat any cutoff as binding.
What a grading scale actually is
Strip away the intimidation and a grading scale is a translator. It takes one input — usually a percentage — and returns a label your school uses to record and compare performance. Most systems stack three layers of translation:
- Score → percentage. Your weighted marks produce a course percentage (if that step is fuzzy, start with weighted grades explained — it's the calculation that feeds everything here).
- Percentage → letter. A band table maps ranges to letters: the low 90s become an A, the 80s a B, and so on.
- Letter → grade point. Each letter gets a number for GPA math (A = 4.0, B = 3.0), which is the subject of how to calculate your GPA.
Every "grade" you see is one of these layers. The confusion isn't the math — it's that different schools and countries use different tables, and nobody tells you which one you're looking at.
The typical US letter-grade scale
The most common scale in US schools maps percentage bands to plus/minus letters like this:
| Percentage | Letter | Percentage | Letter |
|---|---|---|---|
| 93–100 | A | 73–76 | C |
| 90–92 | A− | 70–72 | C− |
| 87–89 | B+ | 67–69 | D+ |
| 83–86 | B | 63–66 | D |
| 80–82 | B− | 60–62 | D− |
| 77–79 | C+ | below 60 | F |
Typical bands only — some schools start the A at 90, skip plus/minus entirely, or set F at below 65. Your school's published table is the one that binds your transcript.
Two things worth noticing. First, the bands aren't equal width: the A− to A jump can be as little as three points, while F covers everything under 60. Second, the boundaries are knife-edges — an 89 and a 90 look almost identical but can be a whole letter apart. That's why the single most valuable question mid-semester is often "how close am I to the next band?" rather than "what's my exact number?"
Letters to GPA points
For GPA, each letter converts to a grade point, typically on a 4.0 scale:
| Letter | Points | Letter | Points |
|---|---|---|---|
| A / A+ | 4.0 | C | 2.0 |
| A− | 3.7 | C− | 1.7 |
| B+ | 3.3 | D+ | 1.3 |
| B | 3.0 | D | 1.0 |
| B− | 2.7 | D− | 0.7 |
| C+ | 2.3 | F | 0.0 |
Typical values. Some schools award A+ a 4.3, some cap everything at 4.0, and some don't use minuses. Check yours.
This is where a scale earns its keep: it lets wildly different courses average together. You can't average "an A− and a C+" directly, but you can average 3.7 and 2.3 to get 3.0. Turning letters into numbers is the whole reason GPA works — the full credit-weighted method lives in how to calculate your GPA.
Pass marks and grade boundaries
A pass mark is just a special boundary on the same scale — the line below which a course doesn't count. Typical pass marks sit at 50% or 60%, but they swing widely: a general-education course might pass at 50%, a nursing or licensure-track course might demand 70% or higher, and some programs require a minimum letter (a C, say) rather than a raw percentage. Never assume; a pass mark is exactly the kind of number your program publishes and enforces.
Grade boundaries — the cutoffs between letters — behave the same way, and rounding is where they bite. Is an 89.4% an 89 (B+) or does it round to 90 (A−)? On a rule that rounds to the nearest whole number, 89.4 stays at 89 and lands a B+, while 89.5 rounds up to 90 and becomes an A−. A tenth of a point can move a letter. Some schools round, some truncate, some round only the final course grade and not the pieces. If you're near a boundary, that policy is worth knowing to the decimal — and if you need a specific score to clear one, what do I need on the final? turns the target into a plan.
International grading systems (the types, not the cutoffs)
Grades don't travel cleanly across borders, because different countries built different kinds of scales. You don't need every country's numbers — you need to recognize the type you're looking at:
- US 4.0 GPA. Letters mapped to a 0–4 point scale, averaged by credit hours. Higher is better; 4.0 is the ceiling (weighted high-school GPAs can exceed it).
- UK degree classifications. Undergraduate degrees are grouped into classes — First, Upper Second (2:1), Lower Second (2:2), Third — based on a weighted percentage average, with pass typically around 40%. The exact boundaries and weighting are set by each university, so confirm your institution's rules.
- Percentage / division systems. Common across South Asia and elsewhere: the grade is the percentage, sometimes bucketed into "divisions" or "distinctions." The headline number looks familiar but the bands behind it differ.
- 10-point CGPA. Many boards and universities use grade points on a 0–10 scale rather than 0–4. The idea is identical to US GPA — just a different ceiling — so a "9.2 CGPA" is read against a 10, not a 4.
- IB Diploma. Each subject is scored 1–7, and the diploma totals out of 45 (six subjects plus core points). It's a points-out-of-a-maximum system; check current IB requirements for the conditions that award the diploma.
- ECTS grades. A European framework that grades relative to the cohort (A for the top band down through E), designed to compare results across countries rather than fix hard percentages.
The honest summary: an "80%" means very different things in different systems, and a 3.5 GPA has no single universal equivalent. Describe the type, then look up the official table — never eyeball a cross-border conversion for anything that matters.
A fully worked conversion
Say a term's course percentages are in hand and you want them as letters, GPA points, and a term GPA. Four courses, three credits each, on the typical US bands above:
| Course | Percentage | Letter | Grade points |
|---|---|---|---|
| Biology | 91 | A− | 3.7 |
| Calculus | 84 | B | 3.0 |
| English | 88 | B+ | 3.3 |
| History | 76 | C | 2.0 |
Reading each row off the band table:
- Biology 91% → falls in 90–92 → A− → 3.7 points
- Calculus 84% → falls in 83–86 → B → 3.0 points
- English 88% → falls in 87–89 → B+ → 3.3 points
- History 76% → falls in 73–76 → C → 2.0 points
Add the grade points and divide (equal credits, so a plain average): (3.7 + 3.0 + 3.3 + 2.0) ÷ 4 = 12.0 ÷ 4 = 3.0 GPA.
Now the subtlety worth internalizing. The raw percentage average is (91 + 84 + 88 + 76) ÷ 4 = 339 ÷ 4 = 84.75% — squarely a B — and the GPA of 3.0 is also a B. They agree here, but they don't always: averaging percentages and averaging grade points are two different operations, and near boundaries they can disagree by a whole letter. When someone converts your GPA back to "a percentage," they're reversing a table that was never one-to-one. That's exactly why converting precisely means using your school's real bands, not a rough chart.
How to read your own scale in five minutes
You don't need to memorize any of the tables above — you need your school's version of them. Find these four things once and every grade snaps into focus:
- The band table. Where do the letters start and stop? (Is the A at 90 or 93?)
- The GPA point values. Is A+ a 4.0 or a 4.3? Are minuses used?
- The rounding rule. Rounded, truncated, or neither — and applied to the pieces or only the final grade?
- The pass mark. The one boundary that decides whether a course counts at all.
All four live in the syllabus, the student handbook, or the registrar's page. Screenshot them once and you'll never wonder what a mark means again — and when you want the arithmetic done for you, the free grade conversion tool at addthismarks.com lets you set those exact bands and point values instead of forcing one "universal" chart onto your school.
FAQ
What percentage is an A? On the typical US scale an A is 93–100% and an A− is 90–92%, though plenty of schools start the A at 90 or drop plus/minus entirely. There's no single universal cutoff — check your school's published band table, because a point or two decides it.
How do I convert a percentage to a GPA? It's a two-step lookup: map the percentage to a letter using your school's band table (88% → B+), then map the letter to grade points (B+ → 3.3). There's no direct percentage-to-GPA formula that works everywhere, so use your institution's own tables for anything official.
What is a typical pass mark? Many courses pass at 50% or 60%, but it varies a lot — some programs require 70% or a minimum letter grade like a C. Because a pass mark is a hard gate, treat only your program's published number as binding.
Why doesn't my GPA match my percentage average? Because averaging percentages and averaging grade points are different operations. A percentage average treats the raw numbers; a GPA averages the letters after the band table has rounded each one into a bucket. Near a boundary the two can land on different letters.
Can I convert grades between countries? You can compare the types of system (a US 4.0, a UK classification, a 10-point CGPA), but there's no reliable universal conversion. Admissions offices use their own tables, so for anything that counts, describe your grade in its own system and let the receiving institution convert it.
Stop translating grades by guesswork. The free grade conversion tool at addthismarks.com turns any mark between percentages, letters, and GPA points using bands you can set to match your school's policy — so a number means the same thing on your report card and in your head. Free, in-browser, no sign-up.
