I Have a 66 in the Class — What Do I Need on the Final?
Going into the final with a 66%: if the final is worth the typical 20%, you need more than a perfect score (an A isn't reachable). Every common weight is below — or set your exact numbers in the calculator.
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What you need at every final-exam weight
| Final worth | For A | For B | For C | For Pass (D) |
|---|---|---|---|---|
| 10% | Not possible | Not possible | Not possible | 6% |
| 15% | Not possible | Not possible | 92.7% | 26% |
| 20% | Not possible | Not possible | 86% | 36% |
| 25% | Not possible | Not possible | 82% | 42% |
| 30% | Not possible | Not possible | 79.3% | 46% |
| 40% | Not possible | Not possible | 76% | 51% |
| 50% | Not possible | 94% | 74% | 54% |
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 66% and a heavily weighted final, your ceiling is 83% (50% weight) to 69.4% (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.
The A is gone — spend the time where it still moves
At 66% with a 20%-weighted final an A is out of reach, and that is genuinely useful information: it means these hours are worth more spent on a course where the letter can still move. Rank your courses by how much a grade can shift per hour before you open a book — the finals-week triage guide is a method for doing exactly that.
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
Why does my school's GPA differ from this one?
Schools differ on three things: whether A+ counts as 4.3 or 4.0, whether plus/minus grades are used at all, and whether honors/AP courses are weighted above 4.0. This calculator uses the most common unweighted convention (A+ = 4.0, minus/plus in 0.3 steps). Your registrar's number is the official one.
How many points is each letter grade worth on a test?
On the standard scale, each letter band spans 10 percentage points, so on a 50-point test a letter grade is about 5 points, and on a 20-point quiz it's about 2. That's why one careless mistake matters more on short assessments — a single 2-point question on a 20-point quiz is an entire letter grade.