Pearson's r measures the strength and direction of the linear relationship between two variables. It ranges from −1 to +1: values near ±1 indicate strong correlation; near 0 indicate weak or absent correlation.
Pearson Correlation Calculator
Calculate the Pearson correlation coefficient (r) and r² between two datasets.
Pearson's r with standard deviation and covariance.
The Pearson correlation coefficient (r) measures the strength and direction of the linear relationship between two continuous variables. It ranges from −1 (perfect negative correlation) to +1 (perfect positive correlation), with 0 indicating no linear correlation. r² indicates the proportion of Y's variance explained by X.
Enter data pairs in the text field.
- Type x, y pairs — one per line. Use comma, semicolon, or space as separator.
- The tool automatically computes r, r², means, standard deviations, and covariance.
- Check the correlation strength classification and interpret the results.
Sources and references for this tool
These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
- NIST/SEMATECH e-Handbook — Pearson Correlation CoefficientNIST — Definition, formula and interpretation of the Pearson correlation coefficient.
- Anscombe's QuartetWikipedia — Classic example of correlation limitations and why visualization complements the number.
- Statistics How To — Pearson rStatistics How To — Practical guide to calculating and interpreting r and r².