Introduction to The TREND Function
The TREND function calculates the values of a given set of X and Y variables and returns additional Yvalues by using the least square method based on a new set of Xvalues along with a linear trend line.
 Syntax
=TREND(known_y’s, [known_x’s], [new_x’s], [const])
 Arguments Description
Argument  Required/ Optional  Description 

known_y’s  Required  A set of dependent yvalues that is already known from the relationship of y = mx + b. Here,

known_x’s  Optional  One or more sets of independent xvalues that is already known from the relationship of y = mx + b.

new_x’s  Optional  One or more sets of new xvalues for which the TREND function calculates the corresponding yvalues.

const  Optional  A logical value specifying how the constant value b from the equation of y = mx + b should be calculated.

 Return Value
Calculated Yvalues along with a linear trend line.
Using the TREND Function in Excel: 3 Examples
Example 1 – Calculating GPA from Exam Scores with The TREND Function
Consider the following example, where we will return the Predicted GPA of the New Score in the right table based on the Exam Score and GPA given in the left table.
Steps:
 Pick a cell to store the result (in our case, it is cell F5).
 Insert the following formula:
=TREND($C$5:$C$13,$B$5:$B$13,E5)
 Press Enter.
 AutoFill the column.
Example 2 – Predicting the Future Value with the TREND Function
We will predict future sales based on monthly sales value. We have sales value from Jan20 to Sep20, and with the TREND function, we will predict the sales from Oct20 to Dec20.
Steps:
 Pick a cell to store the result (in our case, it is cell F5).
 Insert the following formula:
=TREND($C$5:$C$13,$B$5:$B$13,$E$5:$E$7,TRUE)
 Press Enter.
Example 3 – Utilizing Excel’s TREND Function for Multiple Sets of XValues
We have more than one independent variables (Buyers and Other Cost in the first table). We want to calculate the Estimated Sales based on different xvalues (New Buyers and New Cost in the right table).
Steps:
 Pick a cell to store the result (in our case, it is cell I5).
 Insert the following formula:
=TREND($E$5:$E$13,$C$5:$D$13,$G$5:$H$7)
The arrays for the xvalues in the formula are both 2dimensional (C:D and G:H)
 Press Enter.
Things to Remember
 The known values – known_x’s, known_y’s – need to be linear data. Otherwise, the predicted values could be inaccurate.
 When the given values of X, Y, and new X are nonnumeric, and when the const argument is not a Boolean value (TRUE or FALSE), the TREND function throws #VALUE! error.
 If the known X and Y arrays have different lengths, the TREND function returns the #REF error.
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