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Grade Curve Calculator

Apply grade curves to raw exam scores — choose flat points, percentage boost, or the popular square root curve. Enter class scores to see instant curved results. Use the Bell Curve tab to analyze your class distribution and see automatically suggested curve values.

Enter raw scores and choose a curve type to see adjusted scores instantly.

Curve type

Points to add

pts

NameRaw ScoreCurved

67.0

73.0

76.0

79.0

83.0

86.0

88.0

92.0

96.0

100.0

Curve Applied

+5 pts

Every score increased by 5 points (capped at 100)

Class Avg (raw)

79.0

Class Avg (curved)

84.0

Students

How to Use the Grade Curve Calculator

In the Apply Curve tab, select your curve type (flat points, percentage boost, or square root), enter the curve value, and add each student's raw score — curved scores appear instantly alongside class averages before and after. Switch to Bell Curve to enter all class scores and receive automatically generated curve suggestions based on your class distribution.

The Advanced calculator below adds batch curve comparison and multi-scenario analysis. For a complete gradebook with suggested curve targets, side-by-side grade distribution (before vs. after), and standard deviation analytics, scroll to the Professional tier.

Advanced Batch Curve & Curve Scenarios Apply and compare all three curve types side by side

Max Score

Curve Type

Points to Add

Raw %	Raw Grade	Curved Score	Curved %	Curved Grade
72.0%	C-	77.0	77.0%	C+
68.0%	D+	73.0	73.0%	C
85.0%	B	90.0	90.0%	A-
61.0%	D-	66.0	66.0%	D
78.0%	C+	83.0	83.0%	B
55.0%	F	60.0	60.0%	D-

69.8%

Raw Class Average

74.8%

Curved Class Average

5/6

Passing (Raw)

6/6

Passing (Curved)

Types of Grade Curves

1. Flat Points Curve
Curved Score = Raw Score + N points (capped at max)
Example: Raw = 74, Curve = +5 pts → Curved = 79

2. Percentage Boost Curve
Curved Score = Raw Score × (1 + Boost%/100)
Example: Raw = 74, Boost = 10% → 74 × 1.10 = 81.4

3. Square Root Curve
Curved Score = √(Raw Score / Max Score) × Max Score
Example (max = 100): Raw = 64 → √(64/100) × 100 = 80
Raw = 81 → √(81/100) × 100 = 90
Raw = 100 → unchanged = 100

When Do Professors Curve Grades?

Grade curves are applied when an exam was harder than intended and the class average is significantly below the expected target (usually around 75%). Other common reasons include:

• Exam had a known error or ambiguous question
• New professor calibrating difficulty
• Class average fell below department norms
• Historically low scoring exams in a department

Curves are at the professor's discretion and are never guaranteed. Always ask your professor their curving policy before an exam.

Professional Full Gradebook & Analytics Target average, curve suggestions & before/after distribution

Max Score

Curve Type

Points to Add

Target Avg (%)

Raw %	Grade	Curved	Curved %	Curved Grade	Improvement
78.0%	C+	85.0	85.0%	B	+7.0%
62.0%	D-	69.0	69.0%	D+	+7.0%
88.0%	B+	95.0	95.0%	A	+7.0%
71.0%	C-	78.0	78.0%	C+	+7.0%
55.0%	F	62.0	62.0%	D-	+7.0%
83.0%	B	90.0	90.0%	A-	+7.0%
67.0%	D+	74.0	74.0%	C	+7.0%
90.0%	A-	97.0	97.0%	A+	+7.0%
74.0%	C	81.0	81.0%	B-	+7.0%
48.0%	F	55.0	55.0%	F	+7.0%

71.6%

Raw Average

78.6%

Curved Average

13.2

Std Deviation

48 – 90

Score Range

Grade Scale Reference

A+ 97–100 | A 93–96 | A- 90–92 | B+ 87–89 | B 83–86 | B- 80–82
C+ 77–79 | C 73–76 | C- 70–72 | D+ 67–69 | D 63–66 | D- 60–62 | F 0–59

Frequently Asked Questions

A grade curve is an adjustment applied to exam or assignment scores to change the distribution of grades, typically to raise the class average when an exam was harder than intended. The professor applies a mathematical transformation — adding points, multiplying scores, or using a non-linear formula like square root — to shift scores upward. The goal is usually to ensure the class average lands around a target grade like C or B.

Fairness depends on perspective. Flat points give every student an equal absolute boost, which means high scorers benefit proportionally the same as low scorers. Percentage boost gives proportionally larger absolute boosts to higher scorers. Square root curves compress the distribution and give the largest boosts to students who scored lowest, narrowing the gap between top and bottom performers. Most students consider the square root curve fairest because it helps struggling students the most without significantly changing already-high grades.

Not with the curve types in this calculator. All three methods (flat points, percentage boost, square root) are designed to raise scores, not lower them. Scores at or above the maximum are capped at the maximum. Some professors use "curved to a normal distribution" methods that can theoretically lower some scores, but that is not what this calculator implements.

Standard deviation measures how spread out scores are around the average. A low standard deviation means most students scored near the average. A high standard deviation means scores are widely spread from very low to very high. Professors often look at standard deviation when deciding whether to curve — a high standard deviation on a difficult exam might indicate the exam discriminated well but was too hard overall, warranting a curve to raise the mean.

A 5-point flat curve raises your 72% to 77%, moving you from a C to a C+. This calculator shows exactly how any score changes under any curve type — just enter your score and set the curve value.

Absolutely. Use the Bell Curve tab to enter all class scores, then review the suggested curves. The calculator provides a curve to bring the lowest score to 60% and a curve to bring the class average to 75%. You can bring this analysis to your professor as a starting point for discussion. Most professors will consider data-backed suggestions respectfully presented.