Linear regression and correlation calculator
Paste X and Y value pairs and get the regression line (y = a + bx), Pearson's correlation coefficient, R², predictions and a scatter plot with the trend line.
How to useSimple linear regression
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Linear regression and correlation calculator: what it is for
Paste the X and Y value pairs, one per line, straight from Excel or Google Sheets. The tool calculates the least squares regression line, Pearson's correlation coefficient with an interpretation of the strength of the relationship, R², the standard error of the estimate and the predicted Y for any X, and draws the scatter plot with the trend line.
The calculations run in your browser; nothing you type is sent to any server.
How to use
- Paste the X and Y pairs.
- Enter an X to predict Y.
- See the equation, r, R² and the chart.
When to use it
- Analyzing the relationship between two variables.
- Making simple sales forecasts.
- Solving statistics exercises.
Frequently asked questions
How do I paste the data?
One pair per line, with X and Y separated by a space, tab or semicolon. You can copy two columns straight from Excel or Google Sheets. Use a dot or a comma as the decimal separator.
What do r and R² mean?
The correlation coefficient r ranges from −1 to 1 and shows the strength and direction of the linear relationship. R² is the square of r and shows the share of the variation in Y explained by the line: R² = 0.81 means 81% of the variation is explained by X.
Does correlation prove causation?
No. Two variables can move together by coincidence or because both depend on a third factor. Regression shows association, not cause.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.