What grade is 3 wrong out of 18?

3 wrong answers leaves 15 correct, which is 83.3%. That is a B on the standard A–F scale and a B on the plus/minus scale.

Can I give partial credit on an 18-question test?

Yes. On an 18-question test, turn on half points in the Quick Grade calculator and a half-credit answer counts as 2.778% instead of 5.556%. The chart on this page uses whole questions only.

18 Questions

18-Question Grading Scale

Each question on an 18-question test is worth 5.56%. On the common 90/80/70/60 scale you can miss up to 1 question for an A, up to 3 questions for a B, up to 5 questions for a C, up to 7 questions for a D. The chart below shows the percentage and letter grade for every number of wrong answers from 0 to 18.

Custom cutoffs or another test size

Score chart for 18 questions (standard A–F)
Wrong	Correct	Percent	Grade
0	18	100.0%	A
1	17	94.4%	A
2	16	88.9%	B
3	15	83.3%	B
4	14	77.8%	C
5	13	72.2%	C
6	12	66.7%	D
7	11	61.1%	D
8	10	55.6%	F
9	9	50.0%	F
10	8	44.4%	F
11	7	38.9%	F
12	6	33.3%	F
13	5	27.8%	F
14	4	22.2%	F
15	3	16.7%	F
16	2	11.1%	F
17	1	5.6%	F
18	0	0.0%	F

How an 18-question test is scored

Divide the number of correct answers by 18 and multiply by 100. With 18 questions worth the same amount, each one is 5.556% of the grade. An 18-question test is a common size for unit quizzes and chapter tests. One missed question costs 5.56 points, so a single slip rarely decides the letter on its own but two or three often do.

On the common 90/80/70/60 scale you can miss up to 1 question for an A, up to 3 questions for a B, up to 5 questions for a C, up to 7 questions for a D. Anything below the D line is an F.

Quick reference for 18 questions

These scores come from the same chart you see in the tool above.

0 wrong answers (18 correct) = 100.0%, grade A
1 wrong answer (17 correct) = 94.4%, grade A
2 wrong answers (16 correct) = 88.9%, grade B
3 wrong answers (15 correct) = 83.3%, grade B
4 wrong answers (14 correct) = 77.8%, grade C
6 wrong answers (12 correct) = 66.7%, grade D
8 wrong answers (10 correct) = 55.6%, grade F

Rounding and partial credit on 18 questions

Because 18 does not divide 100 evenly, scores are rounded. For example, 2 wrong is 88.8889% exactly and shows as 88.9% rounded to one decimal. The letter is chosen from the rounded value that is displayed.

Half points are possible too: one half-credit answer is worth 2.778%.

Worked example: 2 wrong on an 18-question test

A student misses 2 of 18 questions.

Correct answers: 16 of 18
Percentage: 88.9%
Standard A–F: B
Plus/minus: B+

(18 − 2) ÷ 18 × 100 = 88.89%, so the grade is 88.9% (B).

Grading & Weighting FAQs

Grade Calculator & Scoring FAQs

Clear, mathematically verified answers to common questions about weighted grade averages, grading scales, and final exam target scores.

Each question is worth 100 ÷ 18 = 5.556% when every question has the same weight. Missing one question leaves 94.44%, and each further miss lowers the score by another 5.556 points.

On an 18-question test with the common 90/80/70/60 scale you can miss up to 1 question for an A. For the other letters you can miss up to 3 questions for a B, up to 5 questions for a C, up to 7 questions for a D. Your teacher’s scale may use different cutoffs, so check the syllabus.

Interactive Tools Available

Test a hypothetical score with our Target Grade Simulator above!