NEGBINOM.DIST Function in Excel: Failures Before the k-th Success

NEGBINOM.DIST Function in Excel: Failures Before the k-th Success 1
⏱ 1 min readUpdated 5 October 2026

StatisticsLevel: ExpertAvailable in: Excel 2010+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. NEGBINOM.DIST in practice
  5. Where you will use it
  6. Worked example
  7. Mistakes people make
  8. Related functions

NEGBINOM.DIST gives the chance of a number of failures before reaching a set number of successes, e.g. calls before the 3rd sale.

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Syntax

=NEGBINOM.DIST(number_f, number_s, probability_s, cumulative)
Argument What it means
number_f Failures
number_s Successes needed
probability_s Success chance
cumulative TRUE/FALSE

Examples

Example 1

=ROUND(NEGBINOM.DIST(A2,B2,C2,TRUE),4)

Result: 0.4983. See the worked example table below for more cases.

NEGBINOM.DIST in practice

Where you will use it

  • Calls needed before 3 sales
  • Tests until 2 defects
  • Recruitment funnels

Worked example

FailuresSuccessespFormulaResult
1030.2=ROUND(NEGBINOM.DIST(A2,B2,C2,TRUE),4)0.4983
530.2=ROUND(NEGBINOM.DIST(A3,B3,C3,TRUE),4)0.2031
2020.1=ROUND(NEGBINOM.DIST(A4,B4,C4,TRUE),4)0.6608

Results calculated in Excel.

Mistakes people make

MistakeWhat to do instead
Counting trials, not failuresnumber_f excludes the successes
p as a whole numberUse 0.2

BINOM.DIST

📚 Part of the free Excel course: Beginner → Expert · Try it in the Formula Lab or ask the AI Helper.

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