COMBIN in SoftMaker PlanMaker 2026: Count Unordered Combinations

Imagine a class with eight volunteers and you need a committee of two. A committee of Ava and Ben is the same group as Ben and Ava; order is irrelevant. The number of possible two-person teams is =COMBIN(8,2) = 28. This counts every distinct subset, not the number of permutations/arrangements.

For ordered first, second and third places in a race, PERMUT rather than COMBIN is the appropriate mathematical model. SoftMaker’s manual explicitly contrasts the two and gives PERMUT(10,3) as 720 ordered finishes. In the same situation, COMBIN(10,3) mathematically counts just 120 unordered sets of three finalists. PlanMaker 2026 PERMUT comparison.

• First introduced: Original introduction version is not established. COMBIN is documented by PlanMaker 2021; that is the earliest release checked here, not proof it was added in 2021.
• Current documented status: Supported in the PlanMaker 2026 English reference, whose manual portal also covers NX. The 2026 function reference remains available; this is documentation evidence, not an installed-app result.
• Last supported version / retirement: No retirement or final supported version is established. Supported in 2026 must not be read as “2026 was the last functioning version.”
• Version checks: The named function and input rules were checked in the separate 2021, 2024, and 2026 help entries. These checks do not establish support in every intervening build or FreeOffice licence tier.
• Platforms and editions: No Windows, macOS, Linux, Android or iOS execution was performed. Check the function in the installed edition before relying on platform-specific behaviour or exported workbooks.
• Evidence checked: October 14, 2026 UTC. Native tests: none. Examples are independently calculated expectations. No replacement is required by the checked current reference.

=COMBIN(n, k)

SoftMaker explicitly specifies that both n and k should be integers and that PlanMaker automatically truncates fractional parts. For example, after truncation the mathematical expected value of =COMBIN(10.9,3.8) is that of COMBIN(10,3), namely 120. 2026 official COMBIN entry.

Do not silently relax these limits. Although mathematical binomial coefficients have defined values at k=0 or k=n, the PlanMaker 2026 and 2024 entries explicitly require 0 < k < n. Neither cited entry identifies the precise native error code for equality or a zero selection. This guide therefore does not invent outcomes for =COMBIN(5,0) or =COMBIN(5,5). Also, the 2026 manual lists no function alias or optional argument for COMBIN.

Regional syntax: The examples use the English manual’s comma between the two required arguments. Verify argument separators in your installed PlanMaker locale; if the formula is rejected, use the software’s Formula / Function dialog to insert arguments rather than assuming the separator behaviour of Excel or Google Sheets. No locale-specific execution tests were performed.

Create a new blank sheet. Put Population n in A1, Group size k in B1, COMBIN formula in C1 and Expected count in D1. Enter each population/group-size pair in columns A and B, then type each indicated formula in C2:C11 and check the numerical result against D. The column D numbers below are independently calculated expectations, not cells supplied in a prebuilt workbook.

The paired rows use strictly positive k and larger n, matching the vendor’s documented domain. A larger n does not always produce a very large result: selecting just one from five creates five possibilities; selecting four from 20 produces 4,845 possibilities.

1. Imagine 49 individually numbered balls, of which six different balls are drawn without replacement.
2. In an unused cell, enter =COMBIN(49,6).
3. The vendor’s documented count is 13,983,816, the number of distinct six-element subsets. Official SoftMaker example.

Every unordered combination is one outcome. If the draw order were meaningful—for example an exact first through sixth finish—the mathematical count would instead be an ordered arrangement, and COMBIN would be the wrong model.

Under a simplified assumption that every six-number set is equally likely, one particular six-number set has theoretical probability =1/COMBIN(49,6) ≈ 0.00000007151123842, or 0.000007151123842%. This is a probability calculation derived from the documented count, not a claim about any particular lottery’s prize rules, bonus balls, or actual odds.

A sports program has 12 players and needs a five-player squad with no roles or order assigned. Enter =COMBIN(12,5): the expected number of distinct five-player squads is 792. The same count is obtained by choosing seven to leave out, because mathematically C(12,5) = C(12,7). Use this complement symmetry to cross-check a result when both input pairs satisfy the documented strict domain.

By contrast, if your business must assign named positions to the chosen people, counting unordered groups is insufficient. First decide whether selection order, distinct roles, replacement, and duplicated objects matter; then select the correct combinatorial function.

For integers 0 < k < n, the mathematical count is

n! / (k! * (n-k)!)

The exclamation mark means factorial: multiply the positive integers up to that number. For n=8, k=2, the arithmetic is 8×7÷(2×1)=28. For n=10, k=3, the arithmetic is 10×9×8÷(3×2×1)=120. These examples involve mathematics, not a claim that factorial functions were run in a spreadsheet. Factorial expressions can grow rapidly even where the final combination count remains manageable; use native COMBIN rather than multiplying a great many intermediate large factorials.

The symmetry identity C(n,k)=C(n,n-k) is a good independent check: =COMBIN(10,3) and =COMBIN(10,7) should both be 120 when evaluated in a compatible application. Both inputs satisfy the strict inequalities 0 < k < n. The symmetry says nothing about zero/equal-boundary behaviour in PlanMaker.

For 10 independent yes/no trials in which each outcome is equally likely, the probability of exactly three successes is C(10,3) divided by 2^10. Using spreadsheet syntax, the intended mathematical expression is

=COMBIN(10,3)/2^10

The independently calculated expected fraction is 120/1024 = 0.1171875 (11.71875%). The model requires independent trials with success probability exactly one half; changing the odds requires a different binomial probability formula. SoftMaker lists binomial distribution functions alongside COMBIN in its manual; consult the manufacturer’s COMBIN and related-function section before composing production statistical workflows.

For a more general success probability p, the mathematical probability of exactly k successes out of n independent trials is C(n,k) × p^k × (1-p)^(n-k). Confirm that the cell containing p is numeric and constrained to the interval [0,1].

The official 2026 PlanMaker manual and 2024 PlanMaker manual both name COMBIN(n,k), require n > k > 0, describe decimal truncation and give the same 49-choose-6 lottery calculation. This supports the documentation of the function across two releases—not execution on every device, edition or OS. The SoftMaker manual download catalogue associates the newest documentation with SoftMaker Office NX and 2026. Actual behaviour on individual Windows, Mac, Linux, Android/iOS, FreeOffice editions, and saved XLSX round trips is not tested in these checks.

The independent Microsoft Excel COMBIN reference documents COMBIN(number, number_chosen). It rejects negative n/k and cases where number < number_chosen, but does not impose PlanMaker’s explicit strict k>0 or k<n restrictions in the listed remarks. Therefore, equality/zero are a documented-domain difference, not proof of any particular result in PlanMaker. Excel’s #NUM! and #VALUE! codes described there apply to Excel, not automatically to PlanMaker. Matching names and ordinary counts do not establish binary workbook compatibility. For a migration, save a sample .xlsx, recalculate under both installed applications, and compare boundary cases and display precision before deploying.

• SoftMaker 2026 COMBIN reference — primary current vendor definition and sample.
• SoftMaker 2024 COMBIN reference — previous release check.
• SoftMaker 2026 PERMUT — when order matters.
• Microsoft Excel COMBIN function — separately documented Excel syntax and input rules.
• SoftMaker release/manual index — confirms separate documentation for 2026/NX and 2024.