The Excel GROWTH function predicts exponential growth: it fits the curve y = b·m^x to your known data and returns the predicted y-values for new x-values — the exponential counterpart of TREND.
Syntax
| Argument | Description | |
|---|---|---|
known_ys | Required | The set of y-values you already know from the relationship y = b·m^x. Must be all positive. |
known_xs | Optional | The known x-values. If omitted, Excel uses {1,2,3,...} the same size as known_ys. |
new_xs | Optional | The new x-values for which you want predicted y-values. If omitted, new_xs is assumed equal to known_xs. |
const | Optional | TRUE (or omitted) calculates the constant b normally; FALSE forces b = 1. |
How to use it
GROWTH is a dynamic-array / array formula: it returns one predicted y for each new x, so it spills down (or across) a range. Lay your known points out as two columns and point the new x-values at a third range.
Under the hood GROWTH fits an exponential trend by taking the natural log of the y-values, running a linear regression, then exponentiating the predictions. Because of that log step, every known y-value must be greater than zero — a zero or negative y returns #NUM!.
Use GROWTH when the data roughly doubles/halves over equal steps (populations, viral spread, compound returns). When change is linear instead, use TREND. To see the fitted coefficients themselves, use LOGEST.
Legacy entry: in Excel 2019 and earlier, GROWTH does not spill automatically — select the output range first, type the formula, then press Ctrl+Shift+Enter. In Excel 365 it spills on its own.
Try it: interactive demo
Pick a GROWTH example to see the formula and its result.
Practice workbook
Frequently asked questions
What is the difference between GROWTH and TREND?
TREND fits a straight line (y = mx + b) and predicts linear values; GROWTH fits an exponential curve (y = b·m^x) and predicts values that grow by a constant percentage each step.Why does GROWTH return #NUM!?
#NUM!.Does GROWTH spill automatically?
How do I see the exponential equation GROWTH is using?
LOGEST on the same data — it returns the base m and constant b of the fitted curve y = b·m^x, the coefficients GROWTH applies internally.Master functions like this in one day
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