Correlation Coefficient Calculator

Calculate Pearson's r between two variables.

Enter Your Data Sets

X and Y values must have the same count

X Values

Y Values

Pearson's r

R-Squared (r²)

Data Pairs (n)

Mean X (x̄)

Mean Y (ȳ)

Enter at least 3 X and Y value pairs above to compute Pearson's r.

Step-by-step Solution

Formula

r = Σ(xᵢ−x̄)(yᵢ−ȳ)
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√[Σ(xᵢ−x̄)² × Σ(yᵢ−ȳ)²]

r = Pearson correlation coefficient
x̄, ȳ = Means of X and Y datasets
r² = Coefficient of determination

Interpretation Guide

|r| ≥ 0.9Very Strong

0.7 ≤ |r| < 0.9Strong

0.5 ≤ |r| < 0.7Moderate

0.3 ≤ |r| < 0.5Weak

|r| < 0.3Very Weak / None

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Pro Tips

r ranges from −1 (perfect negative) to +1 (perfect positive). Zero means no linear relationship.

Correlation does not imply causation — a high r only indicates a linear relationship, not cause and effect.