F.DIST in Excel: Calculate F Cumulative Probability and Density

=F.DIST(x, deg_freedom1, deg_freedom2, cumulative)

All four arguments are required in the Microsoft syntax. x is the nonnegative evaluation point; deg_freedom1 is the numerator degree count and deg_freedom2 the denominator degree count. TRUE returns cumulative probability and FALSE returns density.

The degrees follow the order used to construct the F ratio. Exchanging them without changing the ratio generally defines a different distribution. This matters even when both numbers are valid positive integers and the formula returns no error.

Cumulative probability is the area at or below x. Density is a curve height per unit of the F-scale variable. This function does not compute sample variances, decide the ratio orientation or infer degrees from a dataset.

Enter 0, 0.5, 1, 2 and 4 in A2:A6. In B2 enter =F.DIST(A2,2,4,TRUE) and fill down. Independent targets are 0, 0.36, 0.5555555556, 0.75 and 0.8888888889.

For these degree counts, the mathematical cumulative expression is =1-(1+A2/2)^(-2). Put it in C2 and fill down. The check is specific to the two/four distribution; do not retain it after changing the degrees.

A cumulative table increases with x. A decreasing sequence may indicate a right-tail function. Keep the values of x separate from the probability column rather than formatting both as percentages.

Put =F.DIST(A2,2,4,FALSE) in D2 and fill down. Independent density targets are 1, 0.512, 0.2962962963, 0.125 and 0.0370370370.

The elementary density check is =(1+A2/2)^(-3). At x=2 the density is 0.125, while cumulative probability is 0.75. Neither number is the probability of exactly two in this continuous model.

Density at zero depends on the degrees. The finite value one in this example does not establish every native endpoint case. A percentage format does not turn density into probability.

The probability between 0.5 and two is =F.DIST(2,2,4,TRUE)-F.DIST(0.5,2,4,TRUE), independently 0.39.

The upper tail above two is independently 0.25. At this moderate input it equals =1-F.DIST(2,2,4,TRUE). F.DIST.RT is the direct upper-tail function when that event is the intended result.

For a continuous model, including the interval endpoints does not change its probability. Do not subtract density heights to calculate a band: they are not accumulated areas.

=F.DIST(1.5,8,12,TRUE) independently targets 0.74609375. Merely swapping the degrees, =F.DIST(1.5,12,8,TRUE), instead targets 0.7118789053.

The valid reciprocal identity changes the ratio and tail as well: =F.DIST.RT(1/1.5,12,8) targets 0.74609375. The reciprocal of an F variable exchanges numerator and denominator degrees.

This identity helps audit imports from worksheets that define opposite ratio orientations. It does not authorize exchanging just one part of the construction. Keep the source definition of the ratio next to its degree inputs.

The source evaluates x=15.2069, degrees 6 and 4. The cumulative formula independently gives 0.9900000430 and density gives 0.0012237917, consistent with its rounded displays 0.99 and 0.0012238.

Microsoft documents #NUM! for negative x or either degree below one. Noninteger degrees are truncated. It documents #VALUE! for nonnumeric inputs while explicitly allowing the logical cumulative argument in its syntax.

Use positive integer degrees deliberately and supply the required mode. No omitted-mode default is assumed. Native text coercions, all boundary densities and extreme-tail accuracy were not executed.

An F-based statistical interpretation requires a justified reference model. F.DIST itself does not prove that two populations have equal or different variation, and its output is not a probability that such a hypothesis is true.

• Current documentation: the dedicated Microsoft reference lists Excel for Microsoft 365, Excel for Microsoft 365 for Mac, Excel 2024, Excel 2024 for Mac, Excel 2021, Excel 2021 for Mac, Excel 2019, Excel 2016, Excel Web App.
• Introduced: Microsoft’s alphabetical catalog marks F.DIST as introduced in Excel 2010. Exact first build and platform-specific introduction dates remain unverified.
• Last functioning version: unknown; a current help listing is not a last-working-build test.
• Evidence checked: October 15, 2026. Official documentation was freshly retrieved; examples were independently calculated. No native Excel, Mac or web-client execution was performed.

• Microsoft F.DIST reference.
• Microsoft function catalog and introduction-marker explanation.
• Editorial testing standards.

Examples use English function names and comma separators. Expected numbers are rounded independent mathematical calculations; documented error expectations are labeled as such. They are not captured Excel output. All illustrative data and policies are fictional.