BINOMDIST Function (LibreOffice Calc — Legacy)

• Introduced: Documented by LibreOffice 26.8.1.1; original introduction not established.
• Availability: Supported in LibreOffice 26.8.1.1, verified against its function registry. This identifies a supported release, not a final working version.
• Scope: Desktop Calc, using the English function name. Availability in other spreadsheet applications is separate.
• Checked: 2026-10-14 — function reference; versioned support. Documentation/source check; not a new native test. Existing example-specific test claims below retain their stated scope.

Quick answer: =BINOMDIST(2;10;0.2;0) has reference value 0.301989888.

BINOMDIST models the number of successes in a fixed number of independent trials, each with the same success probability. False cumulative mode returns the mass at one success count. True cumulative mode returns the chance of that count or fewer. It does not calculate a continuous density. Pinned calculation logic.

=BINOMDIST(Successes; Trials; Probability; Cumulative)

Exactly four arguments are required. Successes and Trials are rounded down in the inspected implementation; use deliberate integers with 0≤Successes≤Trials. Probability must lie in the closed interval 0 through 1. Cumulative=FALSE or 0 returns P(X=k); TRUE or another nonzero numeric value returns P(X≤k). Trials=0 is allowed when Successes=0.

These eight formulas were recalculated through XLSX import in LibreOfficeDev 26.8.0.0.alpha0, build 2c87e51eeaa2b413ff4ae097b2705eea1995d8e5. Saved ODS values agree with independent high-precision references, rounded here to twelve decimal places. This is headless development-build evidence, not stable-release or GUI validation.

Suppose ten independent items each have a defect probability 0.2. =BINOMDIST(2;10;0.2;FALSE()) gives 0.301989888, the probability of exactly two defects. At most two uses TRUE and gives 0.6777995264.

If a decision threshold is “at least three defects,” use =1-BINOMDIST(2;10;0.2;TRUE()), giving 0.3222004736. “More than three” would instead subtract the cumulative value at 3. Put the written event next to the formula so its inclusive or exclusive boundary can be reviewed without guessing.

An inclusive range from 2 through 4 successes has probability =BINOMDIST(4;10;0.2;TRUE())-BINOMDIST(1;10;0.2;TRUE()), which is 0.591396864. The lower subtraction uses one less than the first included count. If the lower boundary is 0, omit that subtraction rather than asking this function to evaluate −1.

The mass formula is COMBIN(n;k)×p^k×(1−p)^(n−k). It supplies an independent check for moderate counts, but manually assembling enormous factorials can overflow before the final probability is formed. A finite list from 0 through n should total 1 within numerical precision. Sampling without replacement from a small finite population generally calls for a hypergeometric model instead of blindly reusing binomial probabilities.

BINOMDIST and BINOM.DIST share the inspected calculation routine. Their different names do not make the older spelling retired or establish a general accuracy advantage for the dotted spelling. For a range probability, the CDF difference above is explicit; Calc’s separate B function also serves range calculations. A file-format alias is not automatically an English native formula name.

The source handles probability 0 and 1 explicitly. For p=0 all mass is at zero; for p=1 all mass is at n. Zero trials has all mass at zero. Counts outside 0 through n are rejected, including a requested cumulative cutoff above n, even though a mathematical CDF can be extended to 1 there.

=BINOMDIST(2.9;10.9;0.2;FALSE()) uses the floored counts 2 and 10. That coercion can conceal an input mistake. Negative values, out-of-range probabilities and missing arguments require correction rather than automatic substitution. The model’s independence and constant-probability assumptions remain essential.

Development-build boundary checks

The following additional formulas were saved from the same headless import run. Error text is retained as an error, not converted to a successful zero result.

• BINOM.DIST
• BINOM.INV
• COMBIN
• POISSON

The LibreOffice 26.8.1.1 evaluator establishes the product-specific argument and domain rules. Mathematical references and composite examples were independently checked. Native evidence is limited to the eight reference formulas and listed diagnostics in the named development build. A deliberately stale SUM cache changed from 999999 to 3, and an uncached SUM returned 7 after forced recalculation. The earlier ordinary conversion failed the stale-cache control and was excluded. Composite explanatory calculations, stable releases, GUI entry and extreme-parameter accuracy were not established by this run.