Pearson Correlation Coefficient (r) Calculator
Local ProcessingCalculate linear correlation coefficient r (-1 ≤ r ≤ 1) between two continuous variables.
How It Works & Processing Standards
Enter values above to calculate results automatically. Check each input field for guidance and units.
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Choose correlation or covariance under "Calculation". r ranges from −1 to 1; near 1 means both rise together.
What You Can Do
- Correlation r
- covariance ÷ (SD of x × SD of y) — unit-free, from −1 to 1.
- Covariance
- How far both variables deviate from their means in the same direction. Choose population or sample.
How to Use Pearson Correlation Coefficient (r) Calculator
- 1Choose a calculationCorrelation for strength, covariance for the raw value.
- 2Enter x and ySame order and same length.
- 3Interpret|r| ≥ 0.7 is often read as strong, below 0.3 as weak.
Examples
Study hours and scores
Input: x 1, 2, 3, 4, 5 / y 2, 4, 5, 4, 5
Result: 0.774596669241
Sample covariance
Input: x 1, 2, 3, 4 / y 2, 4, 6, 8
Result: 3.33333333333
Common Use Cases
- Ad spend versus revenue
- How two survey questions relate
- Exploring variables before a regression
Frequently Asked Questions (FAQ)
Does high correlation mean causation?
No. It only means the values move together, not that one causes the other.
What if all values in one list are equal?
Its standard deviation is 0, so r is undefined and you are told so.