Statistics
Correlation Coefficient Calculator
Use this correlation calculator to measure the strength and direction of a linear relationship.
Correlation r
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- Mean x
- —
- Mean y
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Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
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What the correlation coefficient calculator solves
Use this correlation calculator to measure the strength and direction of a linear relationship.
Formula
How to use it
- Enter paired x and y lists.
- Keep each pair in the same position.
- Read r from -1 to 1.
How to read the answer
r near 1 is strong positive linear association, r near -1 is strong negative linear association, and r near 0 is weak linear association.
Common mistakes and edge cases
- Correlation does not prove causation.
- Outliers can strongly affect r.
- Nonlinear patterns can have low Pearson correlation.
Worked examples
Moderate positive relationship
Correlation r
0.8528
Negative relationship
Correlation r
-1
Frequently asked questions
What range can r have?+
Pearson r ranges from -1 to 1.
Can correlation be used for curved data?+
Pearson r measures linear association. Curved relationships need different analysis.
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Last updated: May 15, 2026