Quadratic Regression Calculator
Perform quadratic regression on a set of data points. Enter your X and Y values (comma separated) to find the best fit quadratic equation y = ax² + bx + c.
Published by:
isCalculator Editorial Team
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How to use this tool?
This calculator performs quadratic regression (fitting a parabola y = ax² + bx + c) to your data points.
- Enter X Values: Type your X-coordinates separated by commas (e.g.,
1,2,3,4,5). - Enter Y Values: Type the corresponding Y-coordinates separated by commas (e.g.,
2,5,10,17,26). - Click "Calculate": The calculator will compute the best-fit quadratic equation.
Requirements:
- Both lists must have the same number of values (at least 3 points).
- All values must be valid numbers (use a period for decimals, e.g.,
1.5). - No units needed — works with any numeric data.
Output:
- Equation: Shows the fitted parabola with coefficients rounded to 4 decimals.
- R²: Indicates how well the model fits (1 = perfect fit, 0 = no fit).
Previous Results
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Frequently Asked Questions
Quadratic regression fits a second-order polynomial (y = ax² + bx + c) to a set of data points using the least squares method.
At least 3 data points are needed to determine the three coefficients a, b, and c.
R² (coefficient of determination) indicates how well the quadratic model fits the data. A value close to 1 means a good fit.
