TREND Function in Excel: Extend a Straight-Line Trend

TREND Function in Excel: Extend a Straight-Line Trend featured illustration

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⏱ 2 min readUpdated 5 October 2026

StatisticsLevel: ExpertAvailable in: Excel 2007+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. TREND in practice
  5. Where you will use it
  6. Worked example
  7. Mistakes people make
  8. Related functions
  9. Continue learning

TREND fits a straight line and returns values on it, for existing points or new ones. In Excel 365 it spills several forecasts at once.

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Syntax

=TREND(known_ys, [known_xs], [new_xs], [const])
Argument What it means
new_xs The x-values to predict for.

Examples

Example 1

=TREND(C2:C25, A2:A25, A26:A31)

Next six months on the same trend.

TREND in practice

Where you will use it

  • Linear forecast for several months
  • Fill gaps along a straight line
  • Budget projections

Worked example

MonthFormulaResult
7=ROUND(TREND({100,108,115,124,130,139},{1,2,3,4,5,6},A2),1)146.3
8=ROUND(TREND({100,108,115,124,130,139},{1,2,3,4,5,6},A3),1)154
9=ROUND(TREND({100,108,115,124,130,139},{1,2,3,4,5,6},A4),1)161.8

Results calculated in Excel.

Mistakes people make

MistakeWhat to do instead
Curved growthUse GROWTH
Argument orderknown_y's, known_x's, new_x's

FORECAST.LINEAR · GROWTH · SLOPE

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    Practice workbook: Statistics advanced33 tasks on realistic sales data — type your formula, the Check column turns green when it is right. Answers sheet included.
    ⬇ XLSX · 36 KB

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