GradeCalculations

If I Have a 78, What Do I Need on My Final?

Quick answer: With a 78% going in: to hold a C (73%) you can afford to score in the 50s–60s; to reach a B (80%) you need roughly 85–88% if the final is worth 20–30%; and an A− (90%) is mathematically out of reach unless your final is worth 40% or more — and even then you'd need a near-perfect 108% at 40% weight, so it's not happening without extra credit.
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The full table: from a 78, at every common weight

TargetFinal = 15%Final = 20%Final = 30%Final = 40%
Pass with D (63%)0%*3%28%40.5%
Keep a C (73%)44.7%53%61.3%65.5%
Reach C+ (77%)71.3%73%74.7%75.5%
Reach B− (80%)91.3%88%84.7%83%
Reach B (83%)111.3% ✗103% ✗94.7%90.5%
Reach A− (90%)118% ✗108% ✗

*Already secured — even a zero keeps you above this target. ✗ = requires more than 100%, not achievable through the final alone.

What this table teaches

Two patterns worth noticing. First, defending a grade is cheap; climbing is expensive. From a 78, holding your C takes a 50–65% final — but each letter grade above costs roughly 10 extra points on the exam. Second, heavier finals make climbing easier and falling harder. The B that's impossible at 15% weight needs "only" 90.5% at 40% weight — the same lever that could sink you.

Strategic takeaway: if you're at a 78 and the B− is realistic (84.7% at 30% weight), focus your studying there rather than chasing an impossible A. A targeted goal beats a vague "do my best."

Try it yourself: Final Grade Calculator

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Frequently asked questions

Is a 78 a bad grade to have going into a final?

A 78 is a C+ — solidly passing with room to climb. At typical college weights (20–30%), a strong final turns it into a B−; a weak one can still leave you passing. It's one of the most 'live' positions to be in.

What's the highest grade possible from a 78?

At a 30% final weight, a perfect 100% would land you at 84.6% — a solid B. At 40% weight, a perfect final reaches 86.8%. The A range is out of reach at any common weight.

My grade is 78.5 — does the half point matter?

Yes, especially near letter boundaries. A 78.5 needs about 1–2 fewer points on the final for each target than a flat 78. Use your exact decimal in the calculator.

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