I Have a 90 in the Class — What Do I Need on the Final?
Going into the final with a 90%: if the final is worth the typical 20%, you need 90% for an A and 40% for a B. Every common weight is below — or set your exact numbers in the calculator.
Runs entirely in your browser — nothing is saved or sent anywhere.
What you need at every final-exam weight
| Final worth | For A | For B | For C | For Pass (D) |
|---|---|---|---|---|
| 10% | 90% | Locked in ✓ | Locked in ✓ | Locked in ✓ |
| 15% | 90% | 23.3% | Locked in ✓ | Locked in ✓ |
| 20% | 90% | 40% | Locked in ✓ | Locked in ✓ |
| 25% | 90% | 50% | 10% | Locked in ✓ |
| 30% | 90% | 56.7% | 23.3% | Locked in ✓ |
| 40% | 90% | 65% | 40% | 15% |
| 50% | 90% | 70% | 50% | 30% |
Reading this table
"Locked in" means even a zero on the final keeps that grade. "Not possible" means a perfect final still wouldn't get you there — with a 90% and a heavily weighted final, your ceiling is 95% (50% weight) to 91% (10% weight). The math: needed = (target − current × (1 − weight)) ÷ weight.
Worth knowing
Confirm the scale in your syllabus
The 90/80/70/60 letter cutoffs used here are the most common US scale, but plenty of courses curve, use plus/minus bands differently, or set an A at 94. The syllabus — not any calculator — is the contract that counts.
The registrar's number wins
Online gradebooks lag, professors enter marks late, and rounding policies differ by course. Any calculator — including this one — is a planning tool; the transcript is the record.
That is a demanding final. Here is where to put the hours
Needing 90% on a final is a real ask, and the difference between students who hit it and students who do not is rarely hours — it is studying the right thing. Every subject has a specific step where grades break, and revising around it is the most common way to work hard and gain nothing.
We keep free study resources for 13 subjects — what specifically loses students marks in that course, free courses and open textbooks worth the time, and separate plans for whether you have a week or one night. Algebra, Precalculus, Calculus, Statistics, General Chemistry, or all 13 subjects.
Common questions
How are letter grades calculated from percentages?
Most US schools map percentages to letters in 10-point bands: 90–100 is an A range, 80–89 a B range, 70–79 a C range, 60–69 a D range, and below 60 an F. Plus/minus splits each band roughly in thirds (e.g. 90–92 = A-, 93–96 = A, 97+ = A+). Individual schools and professors can and do vary the cutoffs.
Do these calculators store my grades?
No. Everything is computed in your browser the moment you press Calculate — nothing is uploaded, saved or seen by anyone else. Refresh the page and it's gone.