Grade Curve Calculator — What Would a Curve Do to My Score?
Your teacher says the test will be curved — but how much does that actually help? Enter your raw score and pick a curve method: the square-root curve, flat points, or scaling to the top score. You get the curved score and letter grade, plus a side-by-side comparison of all three methods. Everything runs in your browser; nothing is uploaded or tracked.
Worked example: raw 72% (C−) → square-root curve 84.85% (B), flat +8 points → 80% (B−), scaled to a top score of 88 → 81.82% (B−). Same test, three different answers — which is why the method matters.
Three common curves, explained
1. Square-root curve — curved = 10 × √raw
The classic curve. It helps struggling students the most and barely touches high scores, because the square root compresses the top of the scale. 0 and 100 never move.
| Raw score | Curved score | Gain |
|---|---|---|
| 25 | 50.00 | +25.00 |
| 36 | 60.00 | +24.00 |
| 49 | 70.00 | +21.00 |
| 64 | 80.00 | +16.00 |
| 81 | 90.00 | +9.00 |
| 100 | 100.00 | 0 |
2. Flat points — curved = raw + points (capped at 100)
The simplest curve: everyone gets the same number of points. A 72 with +8 becomes 80; a 96 with +8 becomes 100, not 104 — scores stop at the ceiling. It treats every student equally, which is exactly why teachers like it for a test that was a few points too hard across the board.
3. Scale to the top score — curved = raw ÷ top score × 100
The highest score in the class becomes 100 and everyone else is stretched by the same factor. If the top score was 88, a 72 becomes 81.82 and a 44 becomes 50.00. Nobody's rank changes — the order of the class is exactly preserved, only the scale moves.
What a curve can't do
A curve cannot turn a blank exam into a pass: 0 stays 0 under the square-root curve and under scaling. It also cannot fix a grade that was already fair — if the class average was 85, most teachers won't curve at all. And a curve is the teacher's decision, not a right: this calculator shows what each method would do, so you can stop guessing, but the number that counts is the one your teacher actually applies.
Frequently asked questions
What is a grade curve?
A grade curve is an adjustment a teacher applies when a test turned out harder than intended — the raw scores are shifted up so the grades reflect what students knew, not how brutal the exam was. This calculator only does the math: it never decides whether a curve should be applied. That call is your teacher's.
How does the square root curve work?
Multiply the square root of your raw score by 10: curved = 10 × √raw. It lifts low scores the most — 25 becomes 50 (+25), 64 becomes 80 (+16), 81 becomes 90 (+9) — while 0 and 100 stay exactly where they are. A raw 72 becomes 84.85, moving from C− to B.
How does scaling to the top score work?
The highest score in the class becomes 100 and everyone is scaled by the same factor: curved = raw ÷ top score × 100. If the top score was 88, a raw 72 becomes 81.82. Every student keeps their exact ranking, just stretched onto a 0–100 scale.
Can a curve lower my grade?
Not with any of the three methods on this page: the square-root curve never lowers a score between 0 and 100, flat points only add, and scaling to the top score only stretches upward. Some teachers use other schemes, such as a bell curve that re-centers the class average, and those can lower individual grades — this calculator does not do those.
Which curve will my teacher use?
There is no standard — it depends on the teacher and the class. That is why the comparison table shows all three methods for your score at once: a raw 72 is 84.85 under the square-root curve, 77 with 5 flat points, and 81.82 scaled to a top score of 88. Ask your teacher which method (if any) they apply before counting on a curved grade.
How is this different from the test grade calculator?
The test grade calculator grades your raw score exactly as it stands: 42 out of 50 is 84%, a B. This page adjusts that raw score first, then grades the adjusted number. Use the test grade calculator to see what you actually scored, and this one to see what a curve would do to it.