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Statistical function

TREND

Returns values along a linear trend fitted to the data, as an array.

OccasionalDifficulty 1350 · AdvancedUsage rank #126 of 520
Practice · 3 questions →

When to use it

Fits a straight line to known points and returns the fitted or predicted y values as an array. Without new_x it returns the fitted values for the existing x.

The shape of it

Syntax
=TREND(known_ys, [known_xs], [new_xs], [const])

Worked examples

  • Predict one point

    =TREND({2,4,6,9},{1,2,3,4},5) → 11

    One new x.

  • Fitted line

    =TREND({2,4,6,9},{1,2,3,4}) → {1.8,4.1,6.4,8.7}

    Fitted values for the existing points.

  • Several forecasts

    =TREND(B2:B13,A2:A13,{13,14,15}) → {38200,40050,41900}

    Three months ahead at once.

Worth knowing

  • Residuals: actual minus TREND shows where the line misses.
  • Multiple x columns work: TREND(y, x1:x2) fits a plane.
  • The const argument FALSE forces the line through zero.

Where it goes wrong

  • #REF! when the known ranges differ in size.
  • Spills; in old Excel confirm with Ctrl+Shift+Enter.

Related

AVERAGECOUNTCOUNTACOUNTIFCOUNTIFSMAX

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