# Regression Calculator Run simple linear regression on paired numeric data and inspect slope, intercept, correlation, and predictions > Canonical page: https://elysiatools.com/en/tools/regression-calculator - **Category:** Math & Numbers - **Keywords:** regression, linear regression, least squares, trend line, statistics, calculator ## Overview The Regression Calculator performs simple linear regression on paired numeric datasets, providing essential statistical insights including slope, intercept, correlation coefficient, and R-squared values to help you identify trends and make data-driven predictions. ## Inputs - **Data Pairs** (textarea): One pair per line, e.g. 1, 2 2, 3 3, 5 - **X Values (Optional)** (text): Alternative input: 1, 2, 3, 4 - **Y Values (Optional)** (text): Alternative input: 2, 3, 5, 7 - **Prediction X (Optional)** (text): Predict y for a specific x - **Decimal Precision** (number) ## When to use - When you need to determine the relationship between two variables, such as advertising spend and sales revenue. - When you want to calculate a trend line to forecast future values based on historical data points. - When you need to validate the strength of a correlation between two numeric datasets using the least squares method. ## How it works - Input your data pairs either as a list of X,Y coordinates or as separate X and Y series. - Adjust the decimal precision setting to ensure your statistical outputs meet your reporting requirements. - Submit the data to instantly calculate the regression line equation and correlation metrics. - Optionally provide an X value to generate a specific Y-axis prediction based on the calculated model. ## Use cases - Financial forecasting by correlating historical marketing budgets with quarterly sales performance. - Scientific analysis to determine the rate of change between two observed physical variables. - Operational planning by estimating future resource requirements based on past usage trends. ## Frequently asked questions ### What statistical method does this tool use? This tool uses the ordinary least squares (OLS) method to find the best-fitting straight line for your data. ### Can I input data as separate lists? Yes, you can provide X and Y values in separate fields if your data is already organized into two distinct series. ### What does the R-squared value represent? R-squared indicates the proportion of the variance for the dependent variable that's explained by the independent variable in the regression model. ### How do I predict a future value? Enter the desired X value into the 'Prediction X' field, and the calculator will return the corresponding Y value based on the regression formula. ### Is there a limit to the number of data points? 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