Correlation Coefficient Calculator

Summary

Enter two comma-separated datasets and instantly see Pearson's r, r-squared, and the strength of their linear relationship.

How it works

1. Enter dataset X values as comma-separated numbers (e.g. 1, 2, 3, 4, 5).
2. Enter dataset Y values in the same order and with the same count.
3. Click Calculate — the tool validates your inputs and checks for equal lengths.
4. Pearson's r is computed using the standard formula: sum of (xi - x̄)(yi - ȳ) divided by the product of their standard deviations.
5. r-squared is displayed alongside a plain-English interpretation of the correlation strength.
6. A scatter plot is drawn using Chart.js so you can visually confirm the relationship.

Use cases

• Determine whether two financial variables (e.g. sales and ad spend) are linearly related.
• Validate research hypotheses by checking correlation between measurements.
• Explore relationships between student test scores across two subjects.
• Assess whether temperature and ice cream sales move together.
• Check if workout frequency correlates with weight loss.
• Analyze survey responses across two questions for patterns.
• Verify data quality by spotting unexpected correlations between columns.
• Teach or learn statistics concepts with a live, visual calculator.

Frequently Asked Questions