# 3.166 FAQ-1118 How to fit large X/Y data?

Last Update: 12/23/2021

If you have large X/Y data, when you perform fitting on them with linear fit, polynomial fit (especially with high order), multiple linear fit or nonlinear curve fit, you may meet following problems

• Wrong fitting results
• Fit can not converge

To avoid the problems

The problems do not always happen, but if you meet them, please transform the X or Y values to smaller values, such as subtracting the average value of the dataset.

 In the example, the Y values in column B are very large, the image below illustrates how to calculate smaller Y values using the F(x) Column Formula row with the equation B-mean(B). Then we can perform fitting on the new Y values

Keywords:large data, linear fit, polynomial fit, multiple linear regression, nonlinear curve fit, Curve Fit, Fitting, Normalization