Select the first x value (e.g., 'B1') and press ENTER. Select all 'known x' values and press F4 (e.g., '$B$1:$D$1'). To see the correct character for your region refer to the Excel tooltip appearing while you enter the formula). (Note that the character expected by Excel as an arguments separator depends on your Windows regional settings. Select all 'known y' values and press F4 (e.g., '$B$3:$D$3').Įnter Excel's arguments separator, e.g., ',' (comma). Type ' =TREND(' or use the Insert Function ( fx) menu in Excel. Open the internal datasheet and add a new series, e.g., 'Trendline 1'.Ĭalculate the first value of the trendline using the TREND function: To create a trendline in a line chart, add a new series to the line chart, then calculate its values to form a trendline, e.g., by using the TREND function of Excel: