How Many Questions Can You Miss and Still Pass (or Still Get an A)?
The short answer: you can miss up to 10% of the questions and still get an A, 20% for a B, 30% for a C, and 40% to pass — on the standard 90/80/70/60 grading scale. On a 50-question test that means 5 wrong answers still gets you an A, 10 gets you a B, and 20 still keeps you above a failing grade. But the exact numbers depend on how many questions the test has and what grade cutoffs your school uses, so this guide gives you the one formula that works everywhere, plus ready-made miss budgets for every common test size.
The fastest way to use this guide: check any test size with our test grade calculator — plug in your questions and your wrong answers and it gives you the exact score and letter grade.
The Miss-Budget Formula (Works on Any Test)
Every answer below comes from one formula:
Misses allowed = total questions × (1 − grade cutoff), rounded down to the nearest whole question.
Here’s what that means in plain English. To earn an A on the standard scale, you need at least 90% correct. That leaves 10% of the test you can afford to miss. So on a 40-question test, your A budget is 40 × 0.10 = 4 questions. You always round down, because missing 4.2 questions means missing 5 — and 5 misses would drop you below the cutoff.
The four cutoffs on the standard 90/80/70/60 scale:
- A (90%+): you can miss up to 10% of the questions
- B (80%+): you can miss up to 20% of the questions
- C (70%+): you can miss up to 30% of the questions
- Pass (60%+): you can miss up to 40% of the questions
One honest note before the tables: this site’s grading scale puts A− at 90% and uses plus/minus steps, and schools differ — some use 92/85/77 cutoffs, some don’t use plus/minus grades at all. The formula works with your school’s cutoffs; just plug your own numbers in. The tables below use the standard 90/80/70/60 scale.
The Master Miss-Budget Table
This is the table students bookmark. For each common test size, it shows the maximum questions you can get wrong and still land each grade. Every cell was checked against the formula above (misses must satisfy (N − m) / N ≥ cutoff, taking the floor).
| Test size | A (90%+) max misses | B (80%+) max misses | C (70%+) max misses | Pass (60%+) max misses |
|---|---|---|---|---|
| 10 questions | 1 | 2 | 3 | 4 |
| 20 questions | 2 | 4 | 6 | 8 |
| 25 questions | 2 | 5 | 7 | 10 |
| 30 questions | 3 | 6 | 9 | 12 |
| 40 questions | 4 | 8 | 12 | 16 |
| 50 questions | 5 | 10 | 15 | 20 |
| 100 questions | 10 | 20 | 30 | 40 |
How to read it: on a 25-question test, missing 2 or fewer gets you an A. Miss 3, and you’ve fallen into B territory. Miss 11, and you’ve dropped below the 60% pass line. For the most common classroom sizes, we also have dedicated walkthroughs: grading charts for 16–20 question tests are especially popular with teachers.
How the tricky cells work, so you can trust them:
- 25 questions, A: 25 × 0.10 = 2.5, rounded down to 2. Check: 23/25 = 92% (A ✓), but 22/25 = 88% (B+ — not an A). Rounding down is the correct move.
- 25 questions, C: 25 × 0.30 = 7.5, rounded down to 7. Check: 18/25 = 72% (C ✓), but 17/25 = 68% (D). Again, the floor rule holds.
- 10 questions, Pass: 4 misses → 6/10 = 60% exactly. That counts as passing (the cutoff is at least 60%). Five misses gives 50% — a fail.
Three Worked Examples
Let’s run the full score math on three real scenarios, including the exact letter grade on this site’s plus/minus scale (A− starts at 90%, B+ at 87%, B at 83%, B− at 80%).
Example 1: 30 questions, missed 4
Score = 26/30 = 86.67%. On the standard scale that’s a B, and on this site’s plus/minus scale it falls in the B band (83% up to 87%). Grade: B.
Miss-budget check: the A budget on 30 questions is 3 misses, and you missed 4 — one over the line. So close: those 4 misses dropped you from an A to a B. This is the classic “one question too many” case, and it’s why short tests feel so unforgiving.
Example 2: 50 questions, missed 6
Score = 44/50 = 88%. That’s comfortably a B on any scale — and on the plus/minus scale it lands in B+ territory (87% up to 90%). Grade: B+.
Miss-budget check: the A budget on 50 questions is 5 misses. You missed 6 — exactly one over, so the A just barely slips away. Had you gotten one more right, 45/50 = 90% would have landed you an A− on the dot.
Example 3: 25 questions, missed 3
Score = 22/25 = 88%. Same percentage as Example 2, same result: B+ (87% up to 90%).
Miss-budget check: the A budget on 25 questions is only 2 misses. That third wrong answer is expensive — it drops you two full letter bands from an A to a B+. This is the short-test effect in action, and it deserves its own section.
Why Each Miss Hurts More on Short Tests
This is the single most important intuition in this whole guide: each wrong answer costs more on a short test.
- On a 10-question test, every miss costs 10% — one slip and the A is gone (9/10 = 90% is the floor).
- On a 20-question test, every miss costs 5% — two misses and the A is gone.
- On a 50-question test, every miss costs 2% — you can absorb a few bad guesses and recover.
- On a 100-question test, every miss costs 1% — ten wrong answers and you still have an A.
Practically, this means test strategy should change with test length. On a 10-question quiz, there’s no room for careless mistakes — slow down and double-check every answer. On a 100-question exam, a few educated guesses barely move the needle, so don’t burn five minutes agonizing over one question you can probably get right; the math says it’s worth only 1%.
It also means the master table above is most valuable for short tests, where the miss budget is small enough to count on your fingers — and where teachers feel the grading math the most. Speaking of teachers: for teachers grading a stack, our EZ Grader tool turns any raw score into a percentage instantly.
Half Points and Extra Credit: Stretching Your Budget
Real tests aren’t always clean one-question-one-point affairs. Two wrinkles change the miss math:
Partial credit (half points)
If your teacher gives half credit, a wrong answer might only cost you half a question’s worth. In that case, count each half-credit answer as half a miss against your budget. Example: on a 50-question test (A budget = 5 full misses), if you fully missed 4 and got half credit on 2 more, your effective miss total is 4 + 0.5 + 0.5 = 5 — right on the A line. A generous partial-credit policy can effectively extend your miss budget beyond the table.
Extra credit questions
Extra credit adds points to your earned total without adding to the test’s possible total — which means every extra credit point you earn is effectively a free miss you can afford. Missed 6 on a 50-question test but nailed 2 extra credit points? Your effective score becomes 46/50 = 92% — back in A territory. We have a full guide on how teachers score it: how extra credit affects your grade.
What to Do If You’ve Already Missed Too Many
Sometimes the test is over and the number’s already bad. Don’t panic — one bad test rarely decides a semester, because your final grade is a weighted average of everything. The real question isn’t “how many did I miss,” it’s “what do I need on the next test to get back on track?”
Here’s the recovery math in three steps:
- Find your current average. Weight each test by its share of your total grade (the syllabus tells you the weights).
- Set your target. Pick the final letter grade you want — say a B (80%).
- Solve for the unknown. Required score on remaining work = (Target − Current × Weight done) / Weight remaining. Example: you’ve completed 50% of the course at a 72% average and want an 80% final. You need (0.80 − 0.72 × 0.50) / 0.50 = 88% on everything from here on.
That last example shows both the bad news and the good: 88% is a stretch from 72%, but it’s a concrete target — not a vague “do better.” Rather than doing this by hand every time, use our final grade calculator to find exactly what you need on the next test (or the final exam) to hit your goal grade.
The broader lesson: a test where you “missed too many” is data, not a verdict. Convert it into a number, convert the number into a target, and the target into a plan. That’s all the math is for.
Frequently Asked Questions
How many can I miss on a 20-question test and still get an A?
Two. Your A budget is 20 × 10% = 2 misses. Check the math: 18/20 = 90%, exactly the cutoff. A third miss drops you to 17/20 = 85%, which is a B.
Is missing 5 out of 50 bad?
Not at all — 45/50 is 90%, which is an A− on the plus/minus scale (an A on a no-plus/minus 90/80/70/60 scale). Five misses is exactly the maximum A budget for a 50-question test, so you’ve used every miss you’re allowed and still kept the A. Six would be the one that costs you.
Do teachers round up borderline grades?
Sometimes — but never count on it. Rounding policies vary teacher to teacher: some bump an 89.6% to an A−, some record exactly what the numbers say, and some only round if you’ve shown improvement or asked respectfully. The miss budgets in this guide assume no rounding, which is the safe assumption. If your teacher does round, that’s a bonus, not a plan.
Does this miss-budget math work for quizzes too?
Yes — it’s the same formula at any test size. A 10-question quiz: A budget is 1 miss, pass budget is 4. A 5-question pop quiz: 1 miss gets you 80% (a B), and 2 misses is 60% (barely passing). Quizzes are just short tests, and the short-test rule applies: every miss is expensive, so accuracy beats speed.
What if my school uses a different grading scale?
Then use your cutoffs in the same formula: misses allowed = total questions × (1 − your cutoff), rounded down. Some schools use A = 93%, B = 85%, C = 77%. On that scale, a 40-question test gives an A budget of 40 × 7% = 2.8 → 2 misses (stricter than the standard scale’s 4). The table numbers change; the method doesn’t.
The One-Paragraph Version
You can afford to miss 10% of the questions for an A, 20% for a B, 30% for a C, and 40% to pass — on any test, any size. On short tests each miss is brutally expensive (one wrong answer on a 10-question quiz is 10% gone), so the miss budget matters most there. And if a test already went badly, the number isn’t a verdict: run it through our final grade calculator to find exactly what you need on the next one, and turn the miss into a plan.
