Paste two columns of paired data to instantly calculate Pearson's correlation coefficient (r) — with a live scatter plot, regression line, R-squared, and a plain-English interpretation of strength and direction.
Enter your values on the left, then press Calculate.
Pearson's r ranges from -1 to +1. Values near 0 mean little or no linear relationship; near +1 means a strong positive linear relationship; near -1 means a strong negative relationship. R² (r squared) tells you what fraction of the variance in Y is explained by X.
A high correlation never proves cause and effect. The two variables may both be driven by a third unmeasured factor, or the relationship may be coincidental. Always pair correlation analysis with process knowledge before acting.
Pearson r only measures linear relationships. Two variables with a strong curved relationship can have r near zero. Always look at the scatter plot — if the cloud of points isn't roughly straight, consider transformation or a non-linear method.