The Excel NORM.DIST function returns the normal distribution for a value, given a mean and standard deviation — either the cumulative probability (area to the left) or the probability density.
Syntax
| Argument | Description | |
|---|---|---|
x | Required | The value at which to evaluate the distribution. |
mean | Required | The arithmetic mean of the distribution. |
standard_dev | Required | The standard deviation of the distribution. Must be greater than 0. |
cumulative | Required | TRUE returns the cumulative distribution (area to the left of x); FALSE returns the probability density at x. |
How to use it
NORM.DIST describes a bell curve with any mean and standard deviation. The cumulative flag decides what you get back:
With TRUE you get the probability that a value falls at or below x — the area under the curve to the left. With FALSE you get the height of the curve at x (the density), used mainly for plotting the bell shape.
Standard normal shortcut: when the mean is 0 and standard deviation is 1, NORM.DIST(z,0,1,TRUE) equals NORM.S.DIST(z,TRUE). The inverse direction (probability → x) is NORM.INV.
Try it: interactive demo
Pick a NORM.DIST example to see the formula and its result.
Practice workbook
Frequently asked questions
What is the difference between cumulative TRUE and FALSE?
TRUE returns the cumulative probability — the area under the curve to the left of x (e.g. P(X≤42)). FALSE returns the probability density, the height of the bell curve at x, used for plotting.How is NORM.DIST related to NORM.S.DIST?
NORM.S.DIST is the special case with mean 0 and standard deviation 1. So NORM.DIST(z,0,1,TRUE) equals NORM.S.DIST(z,TRUE).How do I go from a probability back to a value?
NORM.INV, the inverse function. =NORM.INV(0.9088,40,1.5) returns about 42 — the x for which the cumulative probability is 0.9088.Is NORM.DIST the same as the old NORMDIST?
NORM.DIST (Excel 2010+) replaces the legacy NORMDIST and gives identical values. The old name still works for compatibility with older workbooks.Master functions like this in one day
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