The Excel F.TEST function returns the two-tailed probability that the variances of two data sets are not significantly different — the p-value of an F-test for equality of variances.
Syntax
| Argument | Description | |
|---|---|---|
array1 | Required | The first array or range of data. |
array2 | Required | The second array or range of data. Each array must contain at least two numeric values. |
How to use it
F.TEST compares the spread of two samples. It computes the ratio of their variances, then returns the two-tailed probability that the two populations have equal variance.
A large p-value (like 0.65 here) means there is no evidence that the variances differ — you would not reject the assumption of equal variance. A small p-value (below 0.05) suggests the two data sets have genuinely different spread.
This matters before running a t-test: many t-tests assume equal variances, so an F.TEST is a common pre-check. Note that F.TEST returns a two-tailed probability, while F.DIST.RT gives the one-tailed area.
Note: both arrays need at least two numbers, and a variance of zero (all identical values) causes a #DIV/0! error. The legacy name is FTEST (no dot).
Try it: interactive demo
Enter two comma-separated samples to build the F.TEST formula.
Practice workbook
Frequently asked questions
What does the F.TEST result mean?
Is F.TEST one-tailed or two-tailed?
F.DIST.RT with the appropriate degrees of freedom.Why would I run an F.TEST?
How is F.TEST different from FTEST?
F.TEST (with the dot) was introduced in Excel 2010; FTEST is the legacy compatibility function for older workbooks.Master functions like this in one day
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