Math & Statistics

What Is Correlation?

Correlation is a statistical measure of how strongly two variables move together. The correlation coefficient ranges from −1 to +1: +1 means they move together perfectly, −1 means they move in perfectly opposite directions, and 0 means there is no linear relationship.

Correlation vs. Causation

Two variables can be correlated without one causing the other; both may be driven by a third factor, or the link may be coincidental.

In Investing

Combining assets with low correlation is the basis of diversification.

🧮 Calculate It Yourself

Put Correlation into practice with these free calculators — no sign-up, nothing stored.

📉 Standard Deviation Calculator Sample and population standard deviation and variance, with a step table. Calculate → 📊 Average Calculator (Mean, Median, Mode) Get the mean, median, mode, range, and sum of any list of numbers. Calculate →

🔗 Related Terms

Linear Regression Standard Deviation Diversification Variance

More Math & Statistics Terms

📖 Browse all glossary terms or explore all free calculators.

Last updated: September 29, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.