EXPON.DIST in FreeOffice PlanMaker: Syntax and Worked Examples

=EXPON.DIST(2,1/3,TRUE) is expected to return approximately 0.4865828810. If the model’s mean waiting time is three minutes, the rate is 1/3 per minute and this is the probability of waiting no more than two minutes.

FALSE returns a probability density, not the probability of an exact waiting time. That distinction is essential for a continuous distribution.

=EXPON.DIST(x, Lambda, Cumulative)
=EXPONDIST(x, Lambda, Cumulative)

All three arguments are required. x must be nonnegative. Lambda must be positive and represents a rate per unit of time. If x is in minutes, Lambda is per minute. The model’s mean waiting time is 1/Lambda, so a mean of three minutes corresponds to 1/3, not 3.

TRUE requests the cumulative distribution F(x)=1−exp(−Lambda×x). FALSE requests density f(x)=Lambda×exp(−Lambda×x). The cumulative result is dimensionless; density has reciprocal-time units.

This model assumes an exponential waiting-time distribution. The formula does not establish that real arrivals have a constant rate, independence or the model’s memoryless property.

1. Enter waiting limit 2 in A2.
2. Enter rate =1/3 in B2.
3. Enter =EXPON.DIST(A2,B2,TRUE) in C2.
4. Enter =EXPON.DIST(A2,B2,FALSE) in D2 to compare the two meanings.

Independent arithmetic gives:

F(2) = 1−exp(−2/3) = 0.486582880967408 approximately
f(2) = (1/3)×exp(−2/3) = 0.171139039677531 approximately

The first result is about 48.6583% at or before two minutes. The second is a density at two minutes; it must not be presented as a 17.1139% chance of waiting exactly two minutes. Under a continuous model, a single exact point has probability zero.

The chance of waiting longer than two minutes is the survival probability exp(−2/3), approximately 0.5134171190. It complements the cumulative probability to one.

To calculate an interval probability from one to two minutes, subtract cumulative values: F(2)−F(1)=exp(−1/3)−exp(−2/3), approximately 0.2031141915. This is an independent mathematical illustration, not an additional application test unless identified in the native section.

Keep time units consistent. Expressing the same two minutes as 120 seconds requires rate 1/180 per second; Lambda×x remains 2/3. Changing x’s unit without changing the rate would describe a different model.

=EXPON.DIST(0,2,FALSE) has expected density 2. That is not an invalid probability: density is not point probability, and its area over an interval produces a probability. By contrast, =EXPON.DIST(0,2,TRUE) has expected cumulative probability 0.

These controls help detect accidental mode swaps. Do not reject a density merely because its numeric value exceeds one, and do not format every density as a percentage without explaining its units.

The help specifies x≥0 and Lambda>0. It does not enumerate every error token or text-conversion rule, so this guide does not invent outputs for negative x, zero rate or malformed logical arguments. Validate those inputs directly.

The official EXPONDIST page describes EXPON.DIST as an identical newer spelling. Both names are covered here. That wording does not mean EXPONDIST is retired or deprecated; it remains documented.

The modern page cites Excel 2010 or later compatibility. This is not an introduction date for PlanMaker or proof of an export roundtrip. Check the target application’s version and the actual formula when sharing a workbook.

Eight direct formulas were calculated in FreeOffice PlanMaker 2024 revision F1238.1005, pairing EXPON.DIST with EXPONDIST. Both names matched density 0.1711390397 and cumulative probability 0.4865828810 approximately at x=2,Lambda=1/3. At x=0,Lambda=2, both returned density 2 and cumulative probability 0. All eight expressions survived PMDX save and reopen, allowing storage namespace prefixes. These are selected formula checks, not a test that real waiting times follow this model.

Selected J2 shows density rounded to 0.17114. J4:J5 show cumulative probability rounded to 0.48658; J6:J7 show density 2 and J8:J9 show cumulative probability 0.

The official FreeOffice PlanMaker 2024 reference was checked October 18, 2026. The installed application is FreeOffice PlanMaker 2024 revision F1238.1005. The original introduction version is not established by this evidence; the current reference does not identify the function as deprecated or retired. No availability claim for a different edition or a 2026 release is implied.

The native section identifies the exact tested subset and outcomes from revision F1238.1005. Cell-reference walkthroughs and additional mathematical controls were not separate native cases. Screenshots show the reopened PMDX workbook; any spelling normalization or endpoint mismatch is stated explicitly. File-exchange notes are vendor guidance, not an Excel-export test. English formulas in this guide use commas; use the separators required by your formula settings.

• EXP
• LN