I Have a 78 in the Class — What Do I Need on the Final?
Going into the final with a 78%: if the final is worth the typical 20%, you need more than a perfect score (an A isn't reachable) and 88% 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 | 98% | Locked in ✓ | Locked in ✓ |
| 15% | Not possible | 91.3% | 24.7% | Locked in ✓ |
| 20% | Not possible | 88% | 38% | Locked in ✓ |
| 25% | Not possible | 86% | 46% | 6% |
| 30% | Not possible | 84.7% | 51.3% | 18% |
| 40% | Not possible | 83% | 58% | 33% |
| 50% | Not possible | 82% | 62% | 42% |
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 78% and a heavily weighted final, your ceiling is 89% (50% weight) to 80.2% (10% weight). The math: needed = (target − current × (1 − weight)) ÷ weight.
Worth knowing
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.
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.
Common questions
What's the difference between weighted and unweighted averages?
An unweighted average treats every score equally: add them up, divide by the count. A weighted average multiplies each category by its share of the grade first — homework 20%, midterms 40%, final 40% — which is how most courses actually work. If your syllabus lists category percentages, you need the weighted version.
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.