EXPON.DIST in ONLYOFFICE Spreadsheet Editor

• Introduced: Original introduction release is not established by the checked sources.
• Available: Listed in current unversioned ONLYOFFICE help, checked October 18, 2026.
• Implementation inspected: Official SDKJS v10.0.0.169, commit 3679e0375a758d7dc59d31337a45461be3525ed8. The snapshot does not prove identical behavior in every installed editor.
• Retired or deprecated: These sources do not establish retirement or formal deprecation. A legacy name alone does not mean the function has been removed.
• Testing: Numerical examples are independent mathematical expectations, and implementation discrepancies are labeled source predictions. No ONLYOFFICE application or calculation-engine execution was performed.

The examples use English function names and commas. Use your locale’s argument separator if different. Retain full precision in formulas; round only the displayed result. The examples describe function mechanics under the stated model, rather than establishing that your observations follow that model.

=EXPON.DIST(x, lambda, cumulative)

All three arguments are required. x is a nonnegative measurement, lambda is a positive rate, and cumulative selects TRUE for the cumulative distribution function (CDF) or FALSE for the probability density function (PDF). Use explicit Boolean values rather than relying on text conversion.

For a waiting time measured in hours, lambda is events per hour. A rate of 2 corresponds to a mean waiting time of 1/2 hour; it is not a mean of 2 hours. The formulas are CDF = 1-EXP(-lambda*x) and PDF = lambda*EXP(-lambda*x). The CDF is unitless; the density is per hour in this example.

A continuous distribution assigns probability zero to one exact value. A density of 0.27067 is therefore not a 27.067% chance of waiting exactly one hour. Probabilities come from areas, or from differences between CDF values.

1. Put 2 in B1 and label A1 “rate per hour.”
2. Put 0, 0.5 and 1 in A4:A6, labeled as hours.
3. Enter =EXPON.DIST(A4,$B$1,TRUE) in B4 and copy through B6.
4. Enter =EXPON.DIST(A4,$B$1,FALSE) in C4 and copy through C6.

For the final row, EXP(-2) is approximately 0.135335283237. Subtracting it from 1 produces the CDF; multiplying it by 2 produces the density. The density at zero is 2, demonstrating why density values need not lie between 0 and 1.

The probability of a wait between half an hour and one hour is =EXPON.DIST(1,2,TRUE)-EXPON.DIST(0.5,2,TRUE), independently 0.232544157935. The chance of waiting longer than one hour is =EXP(-2*1), approximately 0.135335283237. For very small survival probabilities, calculating the exponential directly avoids subtracting two nearly equal numbers through 1-CDF.

If times are converted to minutes, convert the rate to 2/60 per minute. =EXPON.DIST(60,2/60,TRUE) then represents the same one-hour event. Keeping lambda at 2 while changing x to 60 changes the model. An exponential waiting-time model assumes a constant rate and its memoryless form; the function does not test those assumptions against your data.

• The inspected modern function rejects x<0 or lambda<=0 with internal not_numeric, conventionally #NUM!. Thus =EXPON.DIST(1,0,TRUE) is a source-predicted error.
• Zero x is valid. CDF at zero is 0 and PDF at zero is lambda.
• Conversion errors propagate; use numeric cells and genuine TRUE/FALSE values. The modern calculation converts the cumulative input numerically and branches on its truthiness, but that is not a reason to build a workbook around unusual coercions.
• Large lambda*x can underflow the exponential to zero; a displayed CDF of 1 does not establish that the mathematical tail is exactly zero.
• EXPONDIST is not interchangeable in the inspected version. Its legacy guard tests the converted cumulative flag instead of the rate, so every FALSE density request predicts #NUM!. Its TRUE path also fails to reject nonpositive rates. Current help describes both forms, creating a source/help discrepancy. Prefer this modern spelling for the documented density calculation and verify your installed version before replacing old formulas.

The modern function also uses an array argument helper, whereas the legacy body selects a first array element. Scalar equivalence for ordinary positive-rate CDF calls is not proof of identical array behavior.

Recalculate representative formulas when moving a workbook between editors. Matching names do not guarantee identical argument coercion, array behavior, numerical precision or error handling. The scalar formulas here do not establish automatic spill behavior or a general import/export guarantee.

• EXP
• LN

• ONLYOFFICE EXPON.DIST help, checked October 18, 2026.
• Official SDKJS implementation, 6314–6438, tag v10.0.0.169 and exact commit above.