Correlation Calculator
Paste paired numeric observations to measure linear correlation with Pearson r and monotonic rank correlation with Spearman rho.
Calculate Pearson and Spearman correlation
Paste paired numeric observations to measure linear correlation with Pearson r and monotonic rank correlation with Spearman rho.
How to use the correlation calculator
Enter one X,Y pair per line. The calculator ignores blank lines and reports the number of valid pairs, Pearson's product-moment correlation coefficient, Spearman rank correlation, Pearson R² and sample covariance.
Pearson r versus Spearman rho
Pearson r measures the strength and direction of a linear relationship. Values range from −1 to +1 when defined. Spearman rho first converts the observations to ranks, using average ranks for ties, and then measures the correlation of those ranks. Spearman can capture monotonic relationships that are not well described by a straight line.
What R² means here
For a simple two-variable Pearson correlation, squaring r gives R². It describes the fraction of variance associated with the linear relationship in that simple setting. It does not establish a causal mechanism or replace regression diagnostics.
Important limitations
Outliers can strongly change Pearson correlation, restricted ranges can hide relationships, and combining different groups can create misleading aggregate patterns. Inspect the underlying data and its context rather than treating one coefficient as a complete analysis.