Correlation Calculator
Paste two columns of paired numbers to get Pearson's r, r², the line of best fit, a significance test and a scatter plot.
Pearson r
0.9768
very strong positive relationship
r²
0.9542
95.4% of variance in Y explained
p-value
< 0.0001
Significant at 5%
Pairs (n)
10
t = 12.915, df = 8
Line of best fit: y = 3.4909x + 48. Correlation measures a straight-line relationship only, and doesn't mean one variable causes the other.
How to use the Correlation Calculator
- 1Paste your X values in the first box and Y values in the second, one pair per row.
- 2Read Pearson's r, r² and the p-value.
- 3Check the scatter plot for outliers or a curved pattern that a single r can hide.
Frequently asked questions
What is a good correlation coefficient?
As a rough guide, |r| above 0.8 is very strong, 0.6–0.8 strong, 0.4–0.6 moderate and below 0.2 very weak. What matters depends on the field and sample size.
What does r² mean?
The share of the variation in Y explained by a straight-line relationship with X. An r of 0.7 gives an r² of 0.49, or 49%.
Does correlation mean causation?
No. Two variables can move together because of a third factor, by coincidence, or because the effect runs the other way.
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