Correlation measures the strength of a linear relationship from −1 (perfect negative) to +1 (perfect positive).
How to use the Correlation Coefficient Calculator
- X values
- Y values
Results update as you type, and every field accepts the units shown in its menu.
How it works
The covariance of X and Y is divided by the product of their standard deviations.
Inputs explained
| Field | What to enter |
|---|---|
| X values | A list of numbers separated by commas, spaces or new lines |
| Y values | A list of numbers separated by commas, spaces or new lines |
What each result means
- Pearson r = corr([X values], [Y values])
- R² = [Pearson r]^2
- Slope = slope([X values], [Y values])
- Intercept = intercept([X values], [Y values])
Formula
r = Σ(x − x̄)(y − ȳ) ÷ √(Σ(x − x̄)² Σ(y − ȳ)²)Worked example
Inputs — X values: 1, 2, 3, 4, 5, 6; Y values: 2.1, 3.9, 6.2, 7.8, 10.1, 12.2.
Results — Pearson r = 0.9991; R² = 0.99821; Slope = 2.02; Intercept = -0.02.
Frequently asked questions
Does correlation mean causation?
No; a third factor or coincidence can create correlation.
What does R² mean?
The share of variance in Y explained by a straight-line relationship with X.
What formula does the Correlation Coefficient Calculator use?
r = Σ(x − x̄)(y − ȳ) ÷ √(Σ(x − x̄)² Σ(y − ȳ)²).