There are several functions for calculating linear regression in Excel. They allow you to calculate either multiple regression, simple regression or both.
The LineReg function: the LineReg (or Linest) matrix function can be used to calculate both simple linear regression and multiple linear regression in Excel.
The Trend function: the Trend function can be used to calculate only simple linear regression in Excel. In this case, the operation is similar to the StraightReg function.
The Regression option: The Data Analysis option available in your Excel worksheet allows you to obtain complete information for the linear regression.