"If I get a 90% I get an A — how many can I miss?" is a question every student asks after scanning the syllabus and before the test. The answer is a simple reverse calculation — and it's worth knowing so you pace yourself, skip the trap questions, and don't waste precious final minutes on a question that doesn't matter. Here's how many questions you can miss for any grade on any test.
The formula
Max misses = Total questions × (1 − Target decimal)
Where target is the percentage you want as a decimal (90% = 0.90).
Equal-weighted questions
Most multiple-choice and short-answer tests weight every question equally. For a 40-question test at 90% target:
- Max misses = 40 × (1 − 0.90) = 40 × 0.10 = 4 misses
- Score 36/40 = 90% exactly
Common test sizes
| Questions | A (90%) | B (80%) | C (70%) | D (60%) |
|---|---|---|---|---|
| 20 | 2 miss | 4 miss | 6 miss | 8 miss |
| 25 | 2 miss | 5 miss | 7 miss | 10 miss |
| 30 | 3 miss | 6 miss | 9 miss | 12 miss |
| 40 | 4 miss | 8 miss | 12 miss | 16 miss |
| 50 | 5 miss | 10 miss | 15 miss | 20 miss |
| 60 | 6 miss | 12 miss | 18 miss | 24 miss |
| 75 | 7 miss | 15 miss | 22 miss | 30 miss |
| 100 | 10 miss | 20 miss | 30 miss | 40 miss |
Rounding matters
Teachers typically round to nearest whole number, but not always in your favor. A 25-question test:
- Miss 2 = 92% (clear A)
- Miss 3 = 88% (A- or B+ depending on scale)
Know your teacher's rounding policy — some use ≥89.5 as A-, some require exactly 90.
+/- thresholds
For the standard 10-point scale with +/-:
- A (93+): on a 40-question test, miss at most 2 (95%) or 3 (92.5% → A-)
- A- (90+): miss at most 4
- B+ (87+): miss at most 5 (87.5%) or 6 (85% → B)
Every question missed on a 40-question test = 2.5% of your grade on that test.
Weighted questions
When questions are weighted (essays worth more than MC), the "how many" calculation gets more complex. You need to think in terms of points, not questions.
Example: 20 MC (1 pt each) + 5 SA (4 pts each) + 2 essays (30 pts each) = 100 points total.
To earn 90%+ (90 points), you can lose at most 10 points. That could be:
- 5 wrong MC (5 pts lost) + 1 wrong SA (4 pts lost) = 9 pts lost, score 91%
- Or 0 MC wrong + 10% off on one essay (3 pts) + 7 other small losses
Strategic test-taking
Knowing your miss budget changes how you take tests:
- Don't get stuck on hard questions — if you're on track for an A, skip the 1-2 killers and make sure you finish the rest
- Double-check easy questions — missing a gimme because of a careless error is worse than missing a hard one
- Essay pacing — if an essay is worth 30% and you have 1 hour, budget 18 minutes on it (not a typical 10)
- Partial credit hunting — always write something for essay and SA questions; a 40% on a hard essay beats a 0%
Standardized tests
SAT, ACT, AP have their own scaling. Raw-to-scaled varies per test, but common patterns:
- SAT Math: ~55-58 raw correct for 800 scaled
- SAT Reading/Writing: raw score is scaled through section-specific tables; similar logic to miss budget
- ACT: Raw score of ~74-75 (of 75) for a 36 English; ~59-60 (of 60) for 36 Math
- AP Exams: roughly 60-75% raw correct for a 5, 50-60% for a 4, varies by subject
Multi-test average
If one test has 3 total (say midterm + two quizzes + final), the miss budget isn't per-test. You can bomb one and recover. Example: quiz 1 = 70%, quiz 2 = 90%, midterm = 85%, final = ?, target 85 average (equal weighted):
- Average of first 3: (70+90+85) ÷ 3 = 81.67
- Need final such that (81.67 × 3 + final) ÷ 4 = 85
- Final ≥ 95
See the pattern? Early low scores force late heroics. Consistency beats bursts.
Mid-test pacing check
Use your miss budget to manage time during the test. At the halfway point, estimate your current accuracy:
- If you're confident on most answered questions: you have margin — don't panic on the harder second half
- If you've already guessed on several: budget is getting tight — slow down and get partial credit where possible
- If you're unsure about many: review time at the end is essential — flag questions and return
This awareness prevents the common collapse pattern: panic in the final 10 minutes, rushed answers, miss budget blown.
Cumulative-grade effect of a single test
Your score on any one test only matters in proportion to its course weight. If a test is worth 15% of your course grade and you're currently at 88%:
- Score 100% on this test: new grade ≈ 89.8%
- Score 70% on this test: new grade ≈ 85.3%
- Score 0% on this test: new grade ≈ 74.8% (nearly a C)
Small tests (5% weight) barely move the needle; big tests (30%+ weight) dominate. Map your test calendar to weights, not dates — prioritize studying accordingly.
Recovery after a bad test
If you blow a test:
- Request a score breakdown so you know exactly where points were lost
- Identify patterns — careless errors vs content gaps vs time pressure
- Ask about corrections or retakes — some teachers allow half-credit back on corrected errors
- Calculate recovery targets — what do you need on the remaining tests to end at your goal letter grade?
- Adjust study strategy based on the breakdown, not just "study more"
Calculate for your test
Use our test score calculator to compute max misses for any target, total, and weighting combination — instantly, without mental math.