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Correlation Calculator

Compute Pearson correlation and r² from paired X and Y lists of equal length.

Clear formulas
Educational steps
Detail breakdown

Pearson r with r² and count; undefined if either variable has zero variance.

Limitation: Educational linear correlation—does not prove causation.

Jump to calculator · Sources & review

How to Use the Correlation Calculator

Pearson r with r² and count; undefined if either variable has zero variance.

1

Open the Correlation calculator and read field labels.

Match the mode

Educational linear correlation—does not prove causation.

What It Calculates

Pearson r with r² and count; undefined if either variable has zero variance.

Worked Examples

Strong positive

Inputs

xText:1,2,3,4,5
yText:2,4,6,8,10

Result

r = 1

Perfect linear increase.

Moderate

Inputs

xText:1,2,3,4,5
yText:2,4,5,4,5

Result

r ≈ 0.8

Positive but not perfect.

Uncorrelated

Inputs

xText:1,2,3
yText:5,5,5

Result

Error

Zero Y variance.

Check your mode

Educational linear correlation—does not prove causation.

Frequently Asked Questions

Yes. Results keep the precision shown on the page unless the engine requires integers.

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Formulas

Standard definitions with assumptions noted below.

Formula

r ​=​ cov​(​x,y​)​​/​​(​σ_x σ_y​)​

Scientific Background

Standard statistics definitions with assumptions stated on-page. Educational only—not professional certification.

Sources & review

Correlation Calculator documents the references behind its formulas and assumptions. Always treat results as educational estimates, not personalized professional advice.

Last reviewed

July 22, 2026

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