Correlation Coefficient Calculator
Calculate Pearson correlation coefficient (r) between two variables. Measures strength and direction of linear relationships.
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How to use this calculator
r ranges from −1 (perfect negative) to +1 (perfect positive). Values near 0 indicate no linear relationship.
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Enter up to 5 paired X and Y values (both sets must have the same count).
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The calculator computes Pearson r, which ranges from −1 to +1.
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Read the interpretation: strong positive (r > 0.7) means both variables rise together.
Frequently asked questions
What does a correlation of 0 mean?
r = 0 means no linear relationship exists between the two variables. There may still be a non-linear relationship.
What is R² (coefficient of determination)?
R² shows the proportion of variance in Y explained by X. For example, r = 0.9 means R² = 81%, so 81% of the variation in Y is explained by X.
Is correlation the same as causation?
No. Correlation only measures association. Two variables can be correlated due to a third confounding variable or pure coincidence.
Pearson Correlation Coefficient Calculator
How to use the correlation coefficient
Use this correlation coefficient to pearson correlation coefficient (r) between two variables. Enter your values above and get your result in seconds. The tool is free, works on all devices, and keeps your data private — nothing is stored or shared.
How the correlation coefficient works
The correlation coefficient calculator uses standard formulas used in statistical analysis, data science, and research. Enter your inputs, and the tool calculates the result instantly in your browser. No server-side processing means your data stays on your device. Results update in real time as you change inputs.
What does the correlation coefficient measure?
Pearson r measures the strength and direction of the linear relationship between two quantitative variables. Values from −1 to −0.7 indicate strong negative correlation; −0.3 to +0.3 indicate weak or no linear relationship; +0.7 to +1 indicate strong positive correlation.
When to use correlation analysis
Use correlation when you want to know if two continuous variables are related — for example, height and weight, study hours and exam scores, or advertising spend and sales. Always plot a scatter diagram first to check for non-linear patterns that Pearson r would miss.
Correlation coefficient: how it works
Statistical analysis underpins data science, research, quality control, and business intelligence. This tool applies established textbook formulas to your dataset and returns results instantly, eliminating manual calculation errors.
Who uses this tool?
Researchers, students, analysts, and business professionals use it to understand datasets quickly. Whether you are summarising survey responses or checking experiment results, this tool delivers the key figures instantly.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →