The Excel LOGNORM.DIST function returns the lognormal distribution — the distribution of a variable whose natural logarithm is normally distributed, commonly used for stock prices, incomes, and other positive, right-skewed quantities.
Syntax
| Argument | Description | |
|---|---|---|
x | Required | The value at which to evaluate the distribution. Must be greater than 0. |
mean | Required | The mean of ln(x) — the average of the natural logarithm of the variable. |
standard_dev | Required | The standard deviation of ln(x). Must be greater than 0. |
cumulative | Required | TRUE returns the cumulative distribution (CDF); FALSE returns the probability density (PDF). |
How to use it
LOGNORM.DIST models a variable X where ln(X) follows a normal distribution with the given mean and standard_dev. Set cumulative to choose the curve:
Note that mean and standard_dev describe the distribution of ln(x), not of x itself. The variable x must be positive, since you cannot take the log of zero or a negative number.
Inverse: LOGNORM.INV goes the other way — give it a probability and it returns the x-value at that cumulative percentile. LOGNORM.DIST(...,TRUE) and LOGNORM.INV undo each other.
Try it: interactive demo
Pick a LOGNORM.DIST example to see the formula and its result.
Practice workbook
Frequently asked questions
What does the lognormal distribution model?
Are mean and standard_dev for x or for ln(x)?
What does the cumulative argument do?
How is LOGNORM.DIST different from the legacy LOGNORMDIST?
LOGNORMDIST only returned the cumulative value and had no cumulative argument. LOGNORM.DIST adds that flag so you can request the density too; the legacy name still works for compatibility.Master functions like this in one day
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