Wiztag

Grade Curve Calculator

Adjust student grades fairly in seconds.

Used by 2,000+ teachers · No signup · 100% private

Choose a rescaling method

Rescaling method
Rescaling

Enter student scores

How would you like to enter scores?

Separate scores with commas, spaces, or new lines.

About: Linear Rescaling

Shifts every score by a constant. Choose to lift the top score to the maximum, add a fixed number of points, or hit a target mean.

Formula
curved = score + adjustment
Best for
Most exams

Pick a different method on the left to see how it works — your scores stay private to this device.

How It Works

  1. Paste scores. Drop in your class scores, separated by commas, spaces, or new lines.
  2. Pick a method. Choose a curve and set your grading scale and bounds.
  3. Get results. See before/after stats, letter grades, a distribution chart, and download a CSV.

Curving Methods

Linear Rescaling

Shifts every score by a constant. Choose to lift the top score to the maximum, add a fixed number of points, or hit a target mean. Best for: Most exams.

curved = score + adjustment

Ratio (Proportional)

Scales every score by the same factor so the highest score reaches the maximum grade. Keeps proportions intact. Best for: Keeping relative gaps.

curved = score × (max / highestScore)

Bell Curve

Re-centers scores onto a normal distribution using a target mean and standard deviation. Best for: Large classes.

curved = targetMean + z-score × targetStdDev

Square Root

Applies a square-root boost that helps lower scores the most, then rescales by a multiplier or to the maximum grade. Best for: Difficult exams.

curved = √score × factor

Frequently Asked Questions

What does the Grade Curve Calculator do?

It applies the most common curving methods to your class scores in one click. Enter raw scores, select your method, and it outputs adjusted grades with a preview of the distribution shift.

How do I use the Grade Curve Calculator?

Step 1: paste or enter raw scores (comma-separated or one per line). Step 2: select your method (linear, bell, square root, ratio). Step 3: click Calculate. Step 4: review adjusted scores and export to CSV if needed.

What input formats does the calculator accept?

Scores as a single column (one per line), comma-separated on one line, or pasted from Excel. It accepts percentages, raw points, or letter grades and auto-detects most formats.

Can I preview how the curve will affect grades before applying it?

Yes. The calculator shows before/after distributions, average changes, and a visual comparison. Adjust the method settings and preview again until you're confident.

How do I export curved grades from the calculator?

After calculating, click "Download as CSV." The output is formatted for easy pasting into Excel, Google Sheets, or your LMS gradebook.

What if some students are absent or have incomplete scores?

Leave those out and curve only the valid numeric scores. You'll handle incomplete grades separately in your gradebook.

Can I curve different assessment types differently?

The calculator curves one batch at a time. Run it separately for tests and for assignments to apply specific methods to specific assessment types.

Does the calculator store my scores or data?

No. All calculations happen locally in your browser. Your scores are never sent to a server. Close the tab and your data is gone (unless you opt in to saving on your device).

Why did my class average change more or less than expected?

The change depends on your method and starting distribution. Linear curves add the same points; square root and bell curves adjust by percentage or distribution. Check the before/after stats to understand the shift.

Can I adjust the curve strength or intensity?

Some methods offer settings — for example, the bell curve’s target mean and standard deviation. Most methods follow standard formulas; custom curves require manual Excel formulas.

Still have questions? Get in touch.