How do you calculate a test grade?

Divide the number of correct answers by the total number of questions and multiply by 100. A 20-question quiz with 3 wrong is 17 ÷ 20 = 0.85, or 85%. The letter comes from that percentage: on the usual 10-point scale, 85% is a B. This calculator does both steps and shows the whole chart so you can grade the rest of the stack without retyping anything.

What grade is 3 wrong out of 20?

85%, which is a B on a 10-point scale and also a B on the stricter 7-point scale. With plus/minus grading it is a B as well — B+ starts at 87%. Change the scale in the dropdown and the chart updates immediately.

Does this work for points instead of questions?

Yes. Put the total points possible in the first field and the points lost in the second. A 50-point exam that lost 7 points scores 43 ÷ 50 = 86%. The only difference is the chart, which steps one point at a time rather than one question at a time.

How does the curve work?

The curve adds flat percentage points to every score before the letter is picked, which is the most common classroom curve. A raw 85% with a +5 curve becomes 90% and moves from a B to an A. Scores are capped at 100%, so a 98% with a +5 curve shows as 100% rather than 103%. The uncurved percentage is still shown underneath so you can see what changed.

What is the difference between a 10-point and a 7-point grading scale?

The 10-point scale gives each letter a ten-point band: A is 90–100, B is 80–89, and so on. The 7-point scale, still used in parts of the US and in many nursing and pharmacy programs, is harsher — A starts at 93 and the pass line sits at 70 rather than 60. An 85% is a B on both, but a 92% is an A on the 10-point scale and a B on the 7-point one, and a 65% passes on the first and fails on the second. Check the syllabus before assuming.

How many questions can I miss and still get an A?

That depends on the length of the test, and the calculator answers it directly: the thresholds table lists every letter with the fewest correct answers and the most misses that still reach it. On a 20-question quiz graded on a 10-point scale you can miss 2 and keep an A. On a 40-question test you can miss 4. On a 12-question quiz you can miss 1.

Why does my percentage round differently from my teacher's?

Rounding is where most grade disputes actually come from. 89.5% rounds to 90% — an A — if your school rounds to whole numbers, and stays a B if it does not round at all. Use the decimals dropdown to match the policy in your syllabus; the letter grade is chosen from the rounded figure, exactly as a gradebook does it.

Is anything I type sent to a server?

No. The calculator is plain JavaScript running on your own device. Scores, student counts and curves are never uploaded, logged or stored — turn off your connection and the page keeps grading.

Grade Calculator — Test Score Percentage and Letter Grade

Questions / points

Number wrong

Number right

Curve (+ points)

Grading scale

Rounding

Score

—

Letter grade

—

Correct answers

—

What each grade needs on this test

Grade	Percentage	Correct needed	Can miss

Full grading chart

Wrong	Right	Score	Grade

Type how many questions are on the test and how many the student missed. You get the percentage, the letter grade, and a full chart showing the score for every possible number of wrong answers — the same thing an EZ-grader wheel does, only it also handles curves, points-based tests and plus/minus scales. Nothing is uploaded; the arithmetic runs in your browser.

The three scales, side by side

The same percentage is not the same letter everywhere. A 92% is an A in most high schools, a B in a nursing program on the 7-point scale, and an A- at a college that uses plus/minus grading. The syllabus decides — this table just shows how far apart the three can be.

Letter	10-point	7-point	Plus / minus
A	90–100	93–100	93–96 (A 97+ is A+)
B	80–89	85–92	83–86 (B- 80, B+ 87)
C	70–79	77–84	73–76 (C- 70, C+ 77)
D	60–69	70–76	63–66 (D- 60, D+ 67)
F	below 60	below 70	below 60

Worked examples

Test	Arithmetic	Result
20 questions, 3 wrong	17 ÷ 20 = 85%	B on a 10-point scale, B on a 7-point scale
35 questions, 4 wrong	31 ÷ 35 = 88.57%	B on a 10-point scale, B+ with plus/minus grading
50 points possible, 7 lost	43 ÷ 50 = 86%	B — points work the same as questions
20 questions, 3 wrong, +5 curve	85% + 5 = 90%	A — the curve is applied before the letter is picked

Where grade calculators disagree

Two calculators can show the same test as an A and a B. Three things explain nearly all of it, and all three are adjustable above.

Rounding. 89.5% is an A under a round-to-whole policy and a B without one. Most online graders round silently and never say which way.
The scale. A 7-point scale moves the A line from 90 to 93 and the pass line from 60 to 70. Health-science and some AP courses use it.
Curve order. Adding the curve before choosing the letter, as here, is the common classroom practice. A few gradebooks apply it to the course average instead, which produces a different letter on an individual test.

How it works

1
Enter the number of questions Type how many questions the test has, or how many points it is worth. Points and questions are scored identically, so a 50-point exam works the same as a 50-question quiz.
2
Enter how many are wrong Type the number missed. The number correct fills in automatically, and you can type into that field instead if you counted the right answers rather than the wrong ones.
3
Pick a scale and read the chart Choose a 10-point, 7-point or plus/minus scale, add a curve if you are giving one, and read the percentage, the letter grade, and the row-by-row chart for every number of wrong answers.

Your data stays private

All processing happens entirely in your browser. No files, text, or data are ever sent to our servers. You can disconnect from the internet and this tool will still work.

Frequently asked questions

How do you calculate a test grade?: Divide the number of correct answers by the total number of questions and multiply by 100. A 20-question quiz with 3 wrong is 17 ÷ 20 = 0.85, or 85%. The letter comes from that percentage: on the usual 10-point scale, 85% is a B. This calculator does both steps and shows the whole chart so you can grade the rest of the stack without retyping anything.
What grade is 3 wrong out of 20?: 85%, which is a B on a 10-point scale and also a B on the stricter 7-point scale. With plus/minus grading it is a B as well — B+ starts at 87%. Change the scale in the dropdown and the chart updates immediately.
Does this work for points instead of questions?: Yes. Put the total points possible in the first field and the points lost in the second. A 50-point exam that lost 7 points scores 43 ÷ 50 = 86%. The only difference is the chart, which steps one point at a time rather than one question at a time.
How does the curve work?: The curve adds flat percentage points to every score before the letter is picked, which is the most common classroom curve. A raw 85% with a +5 curve becomes 90% and moves from a B to an A. Scores are capped at 100%, so a 98% with a +5 curve shows as 100% rather than 103%. The uncurved percentage is still shown underneath so you can see what changed.
What is the difference between a 10-point and a 7-point grading scale?: The 10-point scale gives each letter a ten-point band: A is 90–100, B is 80–89, and so on. The 7-point scale, still used in parts of the US and in many nursing and pharmacy programs, is harsher — A starts at 93 and the pass line sits at 70 rather than 60. An 85% is a B on both, but a 92% is an A on the 10-point scale and a B on the 7-point one, and a 65% passes on the first and fails on the second. Check the syllabus before assuming.
How many questions can I miss and still get an A?: That depends on the length of the test, and the calculator answers it directly: the thresholds table lists every letter with the fewest correct answers and the most misses that still reach it. On a 20-question quiz graded on a 10-point scale you can miss 2 and keep an A. On a 40-question test you can miss 4. On a 12-question quiz you can miss 1.
Why does my percentage round differently from my teacher's?: Rounding is where most grade disputes actually come from. 89.5% rounds to 90% — an A — if your school rounds to whole numbers, and stays a B if it does not round at all. Use the decimals dropdown to match the policy in your syllabus; the letter grade is chosen from the rounded figure, exactly as a gradebook does it.
Is anything I type sent to a server?: No. The calculator is plain JavaScript running on your own device. Scores, student counts and curves are never uploaded, logged or stored — turn off your connection and the page keeps grading.

From the blog

How to Calculate a Test Grade (and Where Graders Disagree) How test percentages turn into letter grades, where curves and rounding change the answer, and how the scales differ. Read the post →