Pearson Correlation Coefficient Calculator

Calculate Pearson r from paired data

Paste paired X/Y data from a spreadsheet-style table or plain text. The calculator returns Pearson r, R², sample size, and a scatter plot that helps you verify the relationship visually.

• Use two columns with matching X and Y values.
• Check Pearson r for direction and strength.
• Use the scatter plot to look for curves, clusters, or unusual points.

Interpret r, R², and the scatter plot

Pearson r ranges from -1 to 1. Positive values indicate a positive linear relationship, negative values indicate a negative linear relationship, and values near zero suggest weak linear association.

• R² is r squared and removes the sign.
• Correlation describes association, not causation.
• A strong r can still hide non-linear patterns or separate clusters.

Avoid common correlation mistakes

The sample data decreases as X increases, so it produces a negative correlation. The scatter plot makes that downward pattern visible before you rely on the numeric coefficient, and it can reveal curves or clusters that Pearson r alone may hide.