I Have a 80 in the Class — What Do I Need on the Final?
Going into the final with a 80%: if the final is worth the typical 20%, you need more than a perfect score (an A isn't reachable) and 80% 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% | Not possible | 80% | Locked in ✓ | Locked in ✓ |
| 15% | Not possible | 80% | 13.3% | Locked in ✓ |
| 20% | Not possible | 80% | 30% | Locked in ✓ |
| 25% | Not possible | 80% | 40% | Locked in ✓ |
| 30% | Not possible | 80% | 46.7% | 13.3% |
| 40% | Not possible | 80% | 55% | 30% |
| 50% | 100% | 80% | 60% | 40% |
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 80% and a heavily weighted final, your ceiling is 90% (50% weight) to 82% (10% weight). The math: needed = (target − current × (1 − weight)) ÷ weight.
Worth knowing
Ask about rounding before finals week
An 89.5 is an A- in some classes and a B+ in others. Professors have wildly different rounding policies, and the polite time to ask is mid-semester, not the night grades post.
The final isn't all-or-nothing
Because finals are usually worth 20–40%, your semester of work is protecting you more than you think. Run the numbers: the score you actually need is often lower — sometimes dramatically lower — than the panic estimate.
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.