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Correlation calculator

Measure how strongly two sets of numbers move together with the Pearson correlation coefficient.

How it works Report a problem

Predictive Correlation

Pearson Coefficient & Linear Regression Engine

About the Correlation calculator

Measure how strongly two sets of numbers move together with the Pearson correlation coefficient.

How to use the Correlation calculator

  1. Enter the Independent (X) and Dependent (Y) values, separated by commas, with the same number of values in each.
  2. Press Calculate.

Formula and method

r = Cov(X, Y) ÷ (σₓ × σᵧ). The value lies between −1 and 1.

Worked example

X = 5, 10, 15, 20 and Y = 8, 16, 24, 32 give r = 1, a perfect positive correlation.

Tips

  • Correlation does not prove causation.
  • r near 0 means little linear relationship.
  • Outliers can change r a lot.

Frequently asked questions

What is a strong correlation?
Values with an absolute size above about 0.7 are usually considered strong.