On a test graded with the standard 10-point scale, you can miss up to 10% of the questions and still get an A. That is 2 wrong on a 20-question test, 2 wrong on a 25-question test, 5 wrong on a 50-question test and 10 wrong on a 100-question test.

Those numbers come straight from the percentage formula, which is explained in our guide on calculating a grade from a test score. Below you will find tables for common test sizes, a formula you can use for any test, and what changes if your school uses plus/minus grades or a 7-point scale.

How many questions can you miss? (10-point scale)

This table shows the most questions you can get wrong and still reach each letter on the standard 10-point scale, where an A is 90% or more, a B is 80% or more, a C is 70% or more and a D is 60% or more.

Read it like this: on a 25-question test you can miss 2 questions and still get an A (23 out of 25 is 92%). Miss a third and you drop to 88%, which is a B. You can miss 5 and still get a B (exactly 80%), and 7 and still get a C (72%).

How to work it out for any test

If your test is not in the table, use the formula:

1. Pick your target. For an A on the 10-point scale, that is 90.
2. Find the share you can lose. 100 − 90 = 10, so you can lose 10% of the questions.
3. Multiply by the number of questions. On a 40-question test, 40 × 10 ÷ 100 = 4.
4. Round down. You cannot miss part of a question, and rounding up would put you under the target.

Here is an example with a different target. You want at least 85% on a 40-question test. 40 × (100 − 85) ÷ 100 = 40 × 0.15 = 6. So you can miss 6 questions: 34 out of 40 is exactly 85%.

Here is why rounding down matters. On a 25-question test with a 90% target, 25 × 0.10 = 2.5. If you rounded up to 3, you would think you could miss three questions, but 22 out of 25 is only 88%. Rounding down to 2 keeps you at 92%.

Check your own test

If you have a graded paper in front of you, the quickest way to see where you stand is the Easy Grader. Enter the total number of questions, enter how many you got wrong, and it shows your percentage and letter grade straight away. It is also handy for a teacher marking a whole class.

If your school uses plus and minus grades

Many colleges split each letter into plus and minus grades. An A starts at 93% and an A− starts at 90%, so the number of questions you can miss for the top A is smaller. This table shows the most wrong answers allowed for four common cutoffs:

Notice that on a 10-question test you cannot miss a single question and still get a full A (9 out of 10 is 90%, an A−). Whether the “A” you want is an A or an A− depends on which grading scale your school uses. If you are not sure of the cutoffs, enter your percentage in the letter grade calculator and pick the scale from the list.

If your school uses a 7-point scale

On a 7-point scale an A starts at 93%, a B at 85%, a C at 77% and a D at 70%. Each letter is harder to reach, so you can miss fewer questions:

The same 25-question test with 2 wrong answers (92%) is an A on the 10-point scale but only a B on the 7-point scale. That is why it pays to check the scale before you plan.

What about borderline scores?

The tables use exact percentages, so 90% counts as an A and 89.9% does not. Some teachers round 89.5% up to 90% and some do not. If your score lands right on a boundary, see how grade rounding works and ask your teacher which rule they use.

What can change the answer

• Questions thrown out. If a bad question is removed, the total drops. On a 25-question test with one question removed, 24 remain, and you can still miss 2 and keep an A (22 out of 24 is 91.7%).
• Different point values. If questions are worth different amounts, work with points instead. On an 80-point test with a 90% target, you can lose 8 points.
• Partial credit. A question that earns half the points is not fully right or fully wrong. Count the points, not the questions.
• Bonus questions. Extra credit can let you miss more, because the total possible goes up.
• A curve. If the teacher curves the scores, the tables above no longer apply. Ask how the curve works.

Frequently asked questions