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Quick Answer

GROWTH Function

Fits an exponential curve and returns predicted y-values (array).

✓ Excel✓ Google SheetsExcel All versions

Syntax

GROWTH
(known_ys, [known_xs], [new_xs], [const])

Parameters

ParameterDescriptionRequired
known_ysThe dependent (y) values of the known data used to fit the curve.Required
known_xsThe independent (x) values of the known data; defaults to 1,2,3,... if omitted.Optional
new_xsThe x-values at which to predict y. If omitted, the known x-values are reused.Optional
constTRUE (or omitted) fits y = b*m^x; FALSE forces b = 1 (y = m^x).Optional

Basic Example

Predict a single future point on an exponential series

=GROWTH({2,4,8,16,32},{1,2,3,4,5},6)
Result64

The data follows y = 1*2^x, so at x=6 the prediction is 2^6 = 64.

Advanced Examples

Example 1: Predict several points at once

Project multiple future periods

Supply an array of new x-values to get an array of predictions

=GROWTH({2,4,8,16,32},{1,2,3,4,5},{6,7})
Result: {64, 128}
Spills two values: 64 at x=6 and 128 at x=7. In older Excel confirm with Ctrl+Shift+Enter; in Microsoft 365 it spills automatically.

Example 2: Force base only (b = 1)

Known unit-free multiplier

Set const to FALSE

=GROWTH(B2:B12,A2:A12,C2:C5,FALSE)
Result: Predicted y-values with b fixed to 1
Fit becomes y = m^x, dropping the leading coefficient b.

How GROWTH Works

GROWTH fits the model y = b*m^x by taking the natural logarithm of the known y-values and running a linear regression on ln(y), then exponentiating the result back. Because it accepts an array for new_xs, it can return many predictions at once. It is the exponential counterpart to the linear TREND.

1
Provide known data
List known y-values and, optionally, known x-values.
2
Provide new x-values
List the x-points you want to predict (a single cell or a range).
3
Enter as array
Type =GROWTH(known_ys, known_xs, new_xs) and press Enter (or Ctrl+Shift+Enter in legacy Excel).

Important Notes & Limitations

  • Models only an exponential relationship; use TREND for linear patterns.

  • known_xs and known_ys must have the same number of points, or #REF! is returned.

  • Known y-values must be positive, since the fit takes their logarithm; zeros or negatives cause #NUM!.

  • Returns an array, so in pre-dynamic Excel it must be entered as an array formula.

Common Errors & Fixes

#NUM!A known y-value is zero, negative, or blank, so its logarithm is undefined.

Fix: Use only positive known y-values, or shift the data.

#REF!known_xs and known_ys differ in size, or output cannot spill.

Fix: Match the known array sizes and keep output cells empty.

Download Practice File

Practice GROWTH with Real Data

Download a sample CSV file with pre-populated data and practice exercises for the GROWTH function. Works in both Excel and Google Sheets.

Works in Google SheetsCompatible with ExcelIncludes exercises

File format: CSV (comma-separated values) - opens in Excel, Google Sheets, and all spreadsheet apps

Frequently Asked Questions

How is GROWTH different from TREND?
TREND fits a straight line; GROWTH fits an exponential curve y = b*m^x.
Why does GROWTH need positive y-values?
It fits on the logarithm of y, and log(0) and log(negative) are undefined.
Does GROWTH need array entry?
In Microsoft 365 it spills automatically; in older Excel use Ctrl+Shift+Enter.