# Grade Curve Calculator — Flat, Square Root & Bell Curve

> Curve grades with four methods: flat boost, square-root (Texas) curve, scale to the class top, or bell-curve remap. Instant results, free, no sign-up.

- **Category:** Education & Grades
- **Interactive calculator:** https://youcalc.com/en/education-grades/grade-curve-calculator/
- **Price:** Free, no sign-up required

## Overview

A grade curve adjusts raw exam scores upward so that the class distribution better reflects intended performance standards. This calculator supports four common curving methods: a flat point addition, the square-root "Texas" curve, a linear scale-to-top, and a statistical bell-curve remap. Enter your raw score and the relevant class parameters to see your curved result instantly.

## How to read your result

The headline figure is your curved score on a 0–100 scale. Below it, the Score Comparison bar chart draws two horizontal bars side by side — the grey bar is your raw score and the coloured bar is your curved score — both scaled so the full bar width equals 100. The delta line beneath the headline tells you exactly how many points were added (or subtracted) by the curve.

## Method

Flat curve: curvedScore = rawScore + points, clamped to [0, 100]. Square-root curve: curvedScore = √rawScore × 10, clamped to [0, 100]. Linear scale-to-top: curvedScore = rawScore × 100 / topRawScore, clamped to [0, 100]. Bell-curve remap: the raw score is converted to a z-score relative to the class distribution — z = (rawScore − mean) / sd — then placed on the target distribution: curvedScore = targetMean + z × targetSd, clamped to [0, 100]. All four formulas are standard statistical and educational techniques; see the calculator sources for worked examples from Omni Calculator and Grade Calculator.

## Example

- **Setup:** Raw score: 72. Method: flat addition of 8 points.
- **Result:** 72 + 8 = 80. The curved score is 80, an increase of 8 points.

## Frequently asked questions

### What is the square-root (Texas) curve?

Popularised in Texas high schools, this method sets your curved score to √(raw score) × 10. A raw 72 becomes √72 × 10 ≈ 84.9. Lower scores receive a larger boost than higher ones, compressing the distribution toward the top.

### How does the linear scale-to-top method work?

The highest raw score in the class is scaled to exactly 100, and every other score is scaled proportionally. If the class top is 90 and your raw score is 72, your curved score is 72 × 100 / 90 = 80.

### What does the bell-curve remap do?

The bell-curve method uses z-scores to shift and stretch the class distribution. Your raw score is standardised using the class mean and standard deviation, then re-expressed in a new distribution with a different target mean and target standard deviation. For example, a raw 72 with class mean 70, SD 10, remapped to target mean 75, target SD 10 gives a curved score of 77.

### Will my curved score ever exceed 100?

No. All four methods clamp the result to the range 0–100, so no curved score can exceed a perfect 100 or drop below 0.

### Which curving method should I use?

Flat addition is the simplest and most transparent. Square-root curves help struggling students more than high achievers. Scale-to-top is fair when the exam was genuinely too hard. Bell-curve remap is best when you want to shift the whole class to a specific grade distribution.

## Related calculators

- [Test Grade Calculator](https://youcalc.com/en/education-grades/test-grade-calculator/)
- [Class Rank Percentile Calculator](https://youcalc.com/en/education-grades/class-rank-percentile/)
- [Grade Percentage to Letter Grade & GPA Calculator](https://youcalc.com/en/education-grades/grade-percentage-letter/)

## Sources

- https://www.omnicalculator.com/other/grade-curve
- https://gradecalculator.app/grade-curve-calculator/

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Interactive version: https://youcalc.com/en/education-grades/grade-curve-calculator/ · From YouCalc — https://youcalc.com