In this article
CRITBINOM returns the smallest count whose cumulative binomial probability reaches alpha. It is a compatibility function: Excel keeps it so workbooks from Excel 2007 and earlier still calculate, but Microsoft recommends BINOM.INV for new work. Both give the same result.
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Syntax
=CRITBINOM(trials, probability_s, alpha)| Argument | What it means |
|---|---|
trials |
n |
probability_s |
p |
alpha |
Target |
Examples
Example 1
=CRITBINOM(A2,B2,C2)Result: 6. See the worked example table below for more cases.
💡 For new workbooks use BINOM.INV: it gives the same answer and is the name Microsoft keeps documenting.
CRITBINOM in practice
Where you will use it
- Opening and checking older workbooks that use CRITBINOM
- Understanding formulas shared by colleagues on older Excel versions
- Knowing when to swap in BINOM.INV for clarity
Worked example
| n | p | alpha | Formula | Result |
|---|---|---|---|---|
| 100 | 0.03 | 0.95 | =CRITBINOM(A2,B2,C2) | 6 |
| 20 | 0.2 | 0.5 | =CRITBINOM(A3,B3,C3) | 4 |
| 500 | 0.01 | 0.99 | =CRITBINOM(A4,B4,C4) | 11 |
Results calculated in Excel. Same result as BINOM.INV.
Mistakes people make
| Mistake | What to do instead |
|---|---|
| Using CRITBINOM in new files | Prefer BINOM.INV: same result, clearer name, and the function Microsoft keeps improving |
| Mixing old and new names in one model | Pick one style per workbook so formulas are easy to audit |
Related functions
📚 Part of the free Excel course: Beginner → Expert · Try it in the Formula Lab or ask the AI Helper.
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