Class Grade Curve Calculator

Work out class grade curve instantly with clear inputs, formula shown and shareable results.

About Class Grade Curve Calculator

Curving methods differ in what they preserve. A linear shift adds the same marks to everyone and preserves the spread; the standard score method recentres the distribution and preserves relative standing; the square root method compresses the range and helps the lowest scores most.

Formulas

Standard score method

Curved = Target mean + z x Class standard deviation

Linear shift

Curved = Raw score + (Target mean - Class mean)

Square root method

Curved = sqrt(Raw score) x 10

Worked example

With the default values below, Class Grade Curve Calculator returns Curved score (standard score method) of 76.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Your raw score: 64
Class mean score: 58
Class standard deviation: 12
Target mean after curving: 70

Results

Curved score (standard score method): 76.00
Curved score (linear shift): 76.00
Curved score (square root method): 80.00
Standard score: 0.500

Step by step

1Values used
2Standard score method
3Linear shift
4Square root method
5Curved score (standard score method)= 76.00
6Curved score (linear shift)= 76.00
7Curved score (square root method)= 80.00
8Standard score= 0.500

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Which method is fairest?

There is no universal answer. Linear shift is the most transparent; the square root method is the most generous to weak scores and the least defensible statistically.

Does curving change class rank?

Not under linear shift or the standard score method, since both are monotonic transformations. The square root method also preserves rank but compresses differences.