Correlation Calculator
Measure the Pearson correlation between two paired data sets.
Pearson correlation (r)
0.9157
strong positive
r² (variance explained)
83.9%
Pairs
6
Reading r
Pearson's r runs −1 to +1, measuring how tightly points hug a straight line: +1 perfect rise, −1 perfect fall, 0 no linear pattern. Squaring it gives the share of one variable's variance the other explains — r = 0.7 explains about half.
The two classic caveats
Correlation isn't causation — ice cream sales and drownings correlate through summer. And r only sees straight lines: a perfect U-shaped relationship scores near zero. Always plot the data before trusting the number.
Frequently asked questions
- How does the Correlation Calculator work?
- Measure the Pearson correlation between two paired data sets.
- Is the Correlation Calculator free to use?
- Yes. The Correlation Calculator is completely free, runs entirely in your browser, and requires no account or sign-up. Your inputs never leave your device.
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