Least Squares Line Calculator

About this calculator

Ordinary least squares fits the straight line through a set of X-Y data points that minimizes the sum of the squared vertical distances (residuals) between each point and the line — the reason it's called 'least squares.' The slope and intercept have closed-form solutions (slope = Σ(x−x̄)(y−ȳ) ÷ Σ(x−x̄)², intercept = ȳ − slope×x̄), and the correlation coefficient r indicates how well the line actually captures the relationship in the data, from -1 (perfect negative) to +1 (perfect positive).

This calculator takes pasted X and Y data pairs and returns the fitted line's equation, slope, intercept, and correlation coefficient. Statistics and science students learning regression, researchers doing a quick trend analysis, and analysts checking a correlation before committing to a full statistical model use it as a fast way to quantify a linear relationship in a data set without opening a spreadsheet or stats package.