### Using the Grade Curve Calculator

Enter the grades in the box below, one per line. If you have more than one of a grade, you only have to enter it once, although it doesn’t change anything if you leave duplicates in. The calculator filters out duplicates. Enter the minimum and maximum grades for your distribution and press the Calculate button.

### Linear Distribution Equation

If you would rather compute the linear grade distribution by hand, here is the formula that this page uses.

where

Let’s say you gave a test and want scores to be distributed between 60 and 100%. Jimmy scores a raw 72%. The overall minimum score was a 55% and max was 96%.

After scaling, Jimmy now has a 77% instead of his previous 72%.

### Using Excel?

Here’s the formula if you want to punch this into Excel instead.

=SUM(scaled_max + (( scaled_min - scaled_max ) / (raw_min - raw_max)) * (actual_score - raw_max))


The scaled_min, scaled_max, raw_min, and raw_max are whatever the values you want them to be. actual_score should be a reference to the field with the student’s raw score.

### Is a linear grade distribution curve fair?

Fair depends on who you ask. I’d bet that if you asked all of your students whether this curve type is fair the ones that had their grades go up would all consider it fair while the ones with lower grades after the curve would find it unfair.

The times that I’ve used this curve the scaled minimum was never below the raw minimum so everyone went up a bit. I’ve also left really low outliers out of the calculation and then manually changed them to the desired minimum grade.

For example, one student makes a 12% but the next lowest is a 67%. If the 12 was considered as part of the scale it would scale everyone else up unfairly; and that’s actual unfair, not a student’s version of unfair. I’d toss the 12, calculate with the 67 as minimum, and then the 12 would manually scale to the same score as the 67.

### Source

The forumla for this calculator came from eHow.

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## 5 thoughts on “Linear Grade Distribution”

1. Paul says:

What does NaN mean

1. Ryan says:

Not a Number. Where are you seeing that?

2. j says:

No calculate button

1. Ryan says:

There’s not a blue button underneath the field where you enter grades?

What browser are you using? Just checked and it’s showing up in Chrome, FF and Edge.

1. Darren says:

If you only put in one student’s grade it comes back NaN. Once you put more than one grade in the box, the curve is applied. thanks for putting this together!