Linear Regression Calculator
Simple linear regression fits a least-squares line to paired observations so a y value can be estimated from x.
How to use this calculator
- Enter the values requested by the Linear Regression and keep all units consistent.
- Check the formula and worked example before relying on the displayed result.
- Change one input at a time when comparing alternative scenarios.
Formula and method
Slope = Σ[(x − mean x)(y − mean y)] ÷ Σ(x − mean x)²; intercept = mean y − slope × mean x
- The calculator applies the stated relationship to the inputs entered by the visitor. Intermediate calculations use full numeric precision before display rounding.
- Predictions beyond the data range are extrapolations and may be unreliable.
Worked examples
Worked example: Linear Regression
X values 1, 2, 3; Y values 2, 4, 6
The fitted line is y = 2x, so the estimate at x = 4 is 8.
The fitted line is y = 2x, so the estimate at x = 4 is 8.
Understanding the result
Use the output as a calculation for the chosen assumptions, not as an explanation of why a real-world result occurred.
Predictions beyond the data range are extrapolations and may be unreliable.
Important notes
Predictions beyond the data range are extrapolations and may be unreliable.
Confirm the units, source measurements, rounding convention and context before using the result for a real project or decision.
Frequently asked questions
What does this Linear Regression calculate?
Simple linear regression fits a least-squares line to paired observations so a y value can be estimated from x.
Which assumptions matter most?
Predictions beyond the data range are extrapolations and may be unreliable.
Can the result replace professional or domain-specific guidance?
No. The tool provides arithmetic under its stated assumptions; check applicable specifications, accounting conventions, standards or qualified guidance for consequential decisions.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
- How to Calculate Percentage Change — Learn the percentage change formula, how to calculate increases and decreases, and why the original value matters.
- How to Calculate Percent Error — Learn the percent error formula and how to compare an experimental value with a reference or accepted value.
- Percentage Change — Learn what percentage change means, how to calculate increases and decreases, and how the original value affects the result.
This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.