Collabora Office LOGNORMDIST: Log-Space Parameters and Optional Arguments
Explain LOGNORMDIST defaults, positive-support density and CDF behavior, with the distinct four-argument LOGNORM.DIST contract. Scoped to the new Linux desktop source build.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
LOGNORMDIST evaluates a lognormal distribution with unusually permissive legacy defaults: the input value alone is sufficient. The parameters describe the normal distribution of the natural logarithm, not the arithmetic mean and standard deviation of the original positive variable.
Syntax and defaults
=LOGNORMDIST(Number [; Mean [; StDev [; Cumulative]]])
The exact evaluator defaults omitted Mean to 0, StDev to 1, and Cumulative to TRUE. With four arguments, FALSE chooses density and TRUE chooses the cumulative distribution. StDev must be positive.
The related LOGNORM.DIST(Number;Mean;StDev;Cumulative) uses the same evaluator with a four-argument minimum. The legacy one-, two- and three-argument forms are meaningful contracts, not interchangeable spellings of a mandatory four-argument call.
Although the help’s parameter wording calls Number a probability value, the evaluator takes it as x, a value of the random variable. A positive x greater than 1 is valid in the ordinary lognormal model; it is not constrained to be a probability.
Step by step: the default distribution
Enter A2 2 and calculate =LOGNORMDIST(A2). Its full literal form is:
=LOGNORMDIST(2)
With log-mean 0 and log-standard-deviation 1, standardize to z=ln(2), approximately 0.6931471806. The independent lower-tail probability is 0.7558914042, meaning about 75.589% of this mathematical model lies at or below 2.
=LOGNORM.DIST(2;0;1;TRUE) has the same source/math target with all arguments present. =LOGNORMDIST(1) returns expected 0.5, because ln(1)=0 is the center of the underlying normal distribution. Thus 1 is the median of this default lognormal model.
Density is a different quantity
=LOGNORMDIST(2;0;1;FALSE)
The independent density is approximately 0.1568740193. For x>0, the formula is phi((ln(x)-mu)/sigma)/(sigma*x), where phi is the standard normal density. The factor 1/x is essential; simply evaluating a normal density at ln(x) omits the change of scale.
A density is not the probability of an exact value. For a continuous model, a point has probability zero; interval probabilities come from differences of cumulative values. The density also carries inverse units of x and need not be bounded by 1.
Optional parameters change the log-scale model
=LOGNORMDIST(1;1) supplies log-mean 1, leaving sigma=1 and cumulative mode. Its independent result is 0.1586552539, because (ln(1)-1)/1 = -1.
=LOGNORMDIST(1;0;2) supplies a broader log-scale standard deviation, but its CDF at 1 remains 0.5, because ln(1) still equals the log-mean. These examples show why the original-variable value 1 must not be mistaken for a mean parameter.
For the default model, the mathematical arithmetic mean is exp(0+1/2), approximately 1.6487212707, not 0. This is a model identity, not an additional executed spreadsheet result.
Advanced: probability between 1 and 2
Subtract the CDF at the lower bound from the upper-bound CDF: 0.7558914042-0.5, approximately 0.2558914042. A formula can express the same model as =LOGNORMDIST(2)-LOGNORMDIST(1).
The result concerns a stipulated distribution. It does not show that a measured dataset is lognormal, that its parameters were estimated correctly or that an outcome is guaranteed. Values must be positive before taking natural logarithms to estimate log-space parameters.
Nonpositive inputs and invalid sigma
The source distinguishes modes at x≤0. Cumulative =LOGNORMDIST(0) and =LOGNORMDIST(-2;0;1;TRUE) return 0, consistent with positive support. Density =LOGNORMDIST(0;0;1;FALSE) instead reaches internal IllegalArgument. Nonpositive sigma is rejected before either mode, as in =LOGNORMDIST(1;0;0).
These are source-derived branch predictions, not native error screenshots. Omitted trailing arguments are documented/source-supported defaults; this guide does not extend them to every explicit empty-slot or text-coercion case.
Published rounding and precision
The help’s LOGNORMDIST(0.1;0;1) example is displayed as 0.01. Independent calculation gives approximately 0.01065109934, consistent with two-decimal display rounding. Extra digits here are mathematical controls, not a vendor accuracy guarantee or native observation. Very small tail probabilities require care beyond these ordinary controls.
Product, version and verification
This guide is scoped to the new Collabora Office desktop for Linux, package source tag coda-26.04.4.3-1, commit 81339d176148d0d5c81ff05d82540f58f8aaa117. The 26.04 LOGNORMDIST help, exact evaluator and dispatch source were checked October 18, 2026. The Linux package manifest provides the recorded product mapping; it is mutable and is not proof of an installed binary.
No Collabora runtime or calculation engine was executed. All worked values are independent mathematical controls or explicit source predictions; vendor display rounding is identified separately. No screenshots, performance benchmarks or cross-platform tests are claimed. This evidence does not certify Classic, Online, CODE, mobile, Windows or macOS.
“Legacy” distinguishes the function’s spelling and argument contract. The checked registration and current help do not establish that it is retired or deprecated. Its first Collabora introduction release is unknown; upstream release history and file-conversion compatibility are not inferred.