Frequently Asked Questions
Everything you need to know about the Linear Regression Calculator.
How do I enter data?
One x,y pair per line, e.g. 1,2 then 2,3.9 on the next line.
What method does it use?
Ordinary least squares, which minimizes the sum of squared vertical distances between the data points and the fitted line.
What does R² mean?
The coefficient of determination, from 0 to 1, showing what fraction of the variation in y is explained by the linear relationship with x. Closer to 1 means a better fit.
What's the difference between R² and r?
r is the Pearson correlation coefficient (-1 to 1), showing direction and strength of the linear relationship. R² is r squared, showing the proportion of variance explained.
How does the prediction work?
Enter any x value and the tool evaluates the fitted equation y = mx + b at that x.
How many data points do I need?
At least 2, though more points give a more reliable fit.
What if all my x values are the same?
A vertical line has no defined slope in y = mx + b form, so the calculator shows an error in that case.
Does it handle negative numbers?
Yes, both x and y can be negative, positive, or decimal values.
Is my data stored?
No; all computation happens locally in your browser.
Is it free?
Completely free, no sign-up or limits.