Grading Scale Calculator — Free Instant Results
GRADING CALCULATOR

Grading Scale Calculator

Generate a complete grading scale for any number of questions. See every possible score, find out how many you can miss, and print a grading chart for your desk.

Percentage
Letter Grade
Per Question
Can Miss (Pass)

Grading Scale Calculator

How many questions on the test?
How many did the student get wrong?
Questions You Can Miss
Enter total questions and select your target grade

Grade Results

0% N/A
Percentage
Letter Grade
Correct / Total
Grading Scale

Grade Boundary Analysis

What-If Scenarios

Complete Grading Table

Visual Analysis

Score Breakdown

Grade Scale Position

Grade Distribution

Score Curve

Impact Analysis

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Grading Scale Percentages Comparison

Percentage Standard (10-pt) Plus / Minus 7-Point Scale
97-100%AA+A+
93-96%AAA
90-92%AA-A-
88-89%BB+B+
85-87%BBB
83-84%BBB-
80-82%BB-C+
77-79%CC+C
73-76%CCC-
70-72%CC-D
67-69%DD+D
60-66%DD / D-F
Below 60%FFF

The grading scale calculator generates a complete grading chart for any number of questions on your test, quiz, or assignment. Enter your total questions to see every possible score with percentages and letter grades, or use the reverse lookup to find out how many questions you can miss and still reach your target grade.

How to Generate a Grading Scale by Number of Questions

Creating a grading scale for a specific test length takes seconds with this calculator. Start by entering the total number of questions on your assessment into the Total Questions field. This works for anything from a 6-question pop quiz to a 200-question final exam.

Next, enter how many questions were answered incorrectly into the Number Wrong field. Your percentage, letter grade, and a complete grading table generate instantly as you type — no button needed. The table shows every possible score from 0 wrong to all wrong, so you can use it as a reference sheet for the entire class.

Teachers commonly need grading scales for specific test lengths. Whether you have an 8-question quiz, a 10-question pop quiz, a 12-question worksheet, a 13-question vocabulary test, a 14 or 15-question chapter review, a 16-question unit quiz, an 18-question midterm section, a 20-question test, a 25-question exam, a 30-question unit test, a 40-question midterm, or a 50-question final, enter the number above to instantly generate the complete grading scale with percentages and letter grades for every possible score.

Switch to Reverse Lookup mode if a student asks “how many questions can I miss and still get a B?” Select the target grade, and the calculator tells you the exact number of wrong answers allowed. Select your grading scale from the tabs — Standard 10-point, Plus/Minus, or 7-Point — to match your school or district policy. Toggle half-points for tests that use partial credit.

Pro Tip: Print the grading table and tape it to your desk. Teachers who standardize their test lengths to 20 or 25 questions can reuse the same printed chart all semester and skip percentage calculations entirely.

Grading Scale Formula: How Each Wrong Answer Affects Your Percentage

Every question on a test carries equal weight. The grading scale calculator uses this formula to convert wrong answers into a percentage score and letter grade.

Grading Scale Formula:
Percentage = ((Total Questions – Number Wrong) ÷ Total Questions) × 100

Per Question Value = 100 ÷ Total Questions

Example: 22 correct out of 25 = (22 ÷ 25) × 100 = 88.0% = B+

The per-question value is what makes test length so important. On a 10-question quiz, each question is worth 10 percentage points. One wrong answer drops you from 100% to 90%. On a 50-question test, each question is worth only 2%, so one mistake barely changes your grade.

Example: Mr. Patel gives a 20-question biology quiz. A student answered 17 correctly. The calculation: (17 / 20) × 100 = 85%. On the standard 10-point scale, 85% is a B. On the plus/minus scale, 85% is also a B. On the 7-point scale, 85% is still a B. For this test length, each wrong answer costs exactly 5 percentage points — one of the cleanest grading scales you can create.

Tests with 10, 20, 25, or 50 questions produce clean percentage breaks at every score. A 15-question quiz creates awkward percentages like 93.3% and 86.7%, making it harder to set clean grade boundaries. Check the EZ grader for instant grading of individual papers, or use the test grade calculator for assessments where questions carry different point values.

How Many Questions Can You Miss and Still Pass?

This is the question students ask most before an exam, and the answer depends entirely on test length and which grading scale your school uses. The reverse lookup mode above gives you the answer instantly, but understanding the math helps you plan ahead for any assessment.

On the standard 10-point scale, passing starts at 60%. That means you need to get at least 60% of the questions correct. On a 25-question test, 60% of 25 is 15 correct answers, so you can miss up to 10 questions and still pass with a D. For a B (80%), you can miss only 5 out of 25.

Example: Compare a 10-question pop quiz with a 50-question unit test. On the quiz, each wrong answer costs 10%, so missing just 2 drops you from 100% to 80% — barely holding a B. On the unit test, each wrong answer costs only 2%, so missing 2 keeps you at 96% — still a solid A. The 50-question test gives five times more room for error, which is why longer tests are generally considered fairer for students.
Common Mistake: Assuming the same number of wrong answers “costs” the same on every test. Missing 3 out of 10 questions drops you to 70% (a C), but missing 3 out of 30 questions leaves you at 90% (an A). Always check the grading scale for your specific test length before estimating your grade.

The grading scale also matters more than most students realize. On a 20-question test, missing 2 gives you 90%. That is an A on the standard scale but only an A-minus on the plus/minus scale, and the difference can affect your GPA. Students aiming for a specific cumulative GPA should check how their school’s grading scale converts letter grades to grade points.

Half-point scoring changes the grading scale as well. When teachers award partial credit, a student might miss 2.5 questions instead of a whole 3, which can mean the difference between a B and a C on shorter assessments. Toggle the half-point option above to see how partial credit affects the complete grading table for your test length.

For courses where homework, quizzes, and exams count differently toward your final grade, use our grade calculator to see how individual test scores combine with other weighted categories. If you already know your current grade and need to find out what score you need on the final, the quick grader gives you an instant answer.

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Frequently Asked Questions

What is the grading scale for 15 questions?
On a 15-question test using the standard 10-point scale, each question is worth 6.67%. Missing 0 gives you 100% (A), missing 1 gives 93.3% (A), missing 2 gives 86.7% (B), missing 3 gives 80% (B), missing 4 gives 73.3% (C), and missing 5 gives 66.7% (D). Enter 15 in the Total Questions field above to see the complete grading table with every possible score.
How do you calculate a grading scale by points?
Divide the number of correct answers by the total number of questions, then multiply by 100 to get the percentage. For example, 18 correct out of 20 questions equals (18 / 20) × 100 = 90%. The letter grade depends on your grading scale. On the standard 10-point scale, 90% is an A. On a 7-point scale, 90% is an A-minus.
What is the standard grading scale for percentages?
The most common US grading scale uses 10-point intervals: A is 90-100%, B is 80-89%, C is 70-79%, D is 60-69%, and F is below 60%. Some schools use a 7-point scale where A starts at 93%, and others use plus/minus modifiers like A-minus for 90-92%. Select your scale in the calculator above to see exact grade boundaries.
How many questions can I miss out of 25 and still get a B?
On the standard 10-point scale where B starts at 80%, you can miss up to 5 questions out of 25 and still earn a B. Missing 5 gives you 80% (exactly a B), while missing 6 drops you to 76% (a C). Use the Reverse Lookup mode above to check how many you can miss for any target grade on any test length.
Can I create a printable grading chart for my classroom?
Yes. Enter the number of questions on your test and the calculator generates a complete grading table showing every possible score with its percentage and letter grade. Click the Print Grading Sheet button to print a clean reference chart you can keep at your desk. The printed sheet works for any grading scale you select.