What-If Grade Calculator
| ASSIGNMENT | ACTUAL PTS | WHAT-IF PTS | OUT OF | DROP |
|---|
Score needed = (target − current × (1 − weight)) ÷ weight
That one line answers the question I get most in December and May: what do I need on the final? This what-if grade calculator does the arithmetic. Give it your current grade, the final's weight, and the grade you want. It also runs the other direction, so you can see where you'd land with a 70, 80 or 90.
Try it with real numbers
You're at 84% going into the final. The final is worth 25%. You want an 87 to keep a B+.
Everything before the final is locked in at 75% of the grade: 84 × 0.75 = 63. So you need (87 − 63) ÷ 0.25 = 96%.
Oof. What if you'd settle for an 85? (85 − 63) ÷ 0.25 = 88%. A lot more realistic. Seeing both side by side is useful, honestly, because it tells you where to put your study hours instead of just stressing about one number.
Reading the result
Over 100? The target can't be reached on the final alone. You'd need extra credit, a curve, or a different goal.
Below zero? You've already locked that grade in. Nice.
The reverse formula, if you want to check "what if I get a 72":
Final grade = current × (1 − weight) + test score × weight
84 × 0.75 + 72 × 0.25 = 63 + 18 = 81%.
Where people get it wrong
Their current grade is off. If the portal is missing a score, or counts ungraded work as zero, the "needed" number will be wrong too. Work out your real grade first with the class grade calculator.
The weight is off. "20% of the semester" is not 20% of the year. This one gets a lot of people.
Points-based classes. The final's weight is its points divided by the course total. A 150-point final in a 750-point course is worth 20%.
Two tests left. Run it twice. First the unit test using your current grade, then the final using your new grade.
Cutoffs. If your teacher treats 89.5 as an A-, aiming for 90 is aiming slightly too high. Our letter grade calculator lists the usual cutoffs.
We also wrote a longer piece on how to calculate what grade you need on your final if you want to see the formula worked through slowly.
One more thing. A target you can actually hit beats a perfect one that has you discouraged by midnight.
Using it a few weeks early
Most people open this the night before a final. Try it three or four weeks out instead. You'll see what each remaining quiz or project is worth, and small wins add up long before exam day.
Say there's a 10% project and a 25% final left, and you're at 84. Nail the project with a 95 and your grade before the final moves to about 85.5. Now the 87 target needs roughly a 92 on the final instead of a 96. Still hard, but noticeably closer.
That's the real value here: it turns "I need to do well" into a specific number you can plan around.
Frequently asked questions
How do I figure out what I need on the final?
Subtract current grade × (1 − final weight) from your target, then divide by the final weight. At 84 with a 25% final and a target of 87, you need 96.
It says I need 104%. What does that mean?
The final alone can't get you there. You'd need extra credit, a curve, or a slightly lower target.
How much does the final move my grade?
Take the gap between your exam score and current grade and multiply by the weight. Scoring 12 below your average on a 25% final costs you 3 points.
Does this work for a regular test too?
Yes. Use that test's weight instead of the final's.
My class uses points, not percentages.
Divide the final's points by total course points to get its weight. 200 out of 1,000 is 20%.
From the blog
Want the reasoning behind the numbers? These guides go a bit deeper.