CONFIDENCE.T
Quirk foundCategory: Statistical · Last tested 2026-09-01
Real compatibility results for the CONFIDENCE.T function: executed in Excel for the web, Google Sheets and LibreOffice Calc, with desktop Excel behavior from Microsoft’s official documentation (we do not run desktop Excel — Excel for the web is a different application and is executed separately). Syntax and links to that documentation are below.
Support matrix
| Engine | Documented | Live-tested | Verdict |
|---|---|---|---|
| Excel (desktop) | Yes | No — documented only | n/a |
| Excel for the web | — | Yes (recalc, 2026-09-01) | Supported, behaves as documented |
| Google Sheets | Yes | Yes (Drive import, 2026-08-31) | Quirk found |
| LibreOffice Calc | Yes | Yes (25.8.7.3, 2026-08-31) | Quirk found |
LibreOffice version history
We executed the same test cases under each LibreOffice release to show exactly when CONFIDENCE.T’s support changed — not documentation claims, real results.
| LibreOffice version | Verdict | Tested |
|---|---|---|
| 24.2.0.3 | Quirk found | 2026-08-31 |
| 24.8.7.2 | Quirk found | 2026-08-31 |
| 25.2.0.3 | Quirk found | 2026-08-31 |
| 25.8.7.3 | Quirk found | 2026-08-31 |
Why isn't CONFIDENCE.T working in LibreOffice?
CONFIDENCE.T exists in LibreOffice 25.8.7.3, but it is not a drop-in match for
Excel — our executed tests found real behavioral differences (detailed in the test results on this
page). If a formula that works in Excel or Google Sheets misbehaves in LibreOffice, compare your usage
against the failing cases above before assuming your data is wrong.
Why isn’t CONFIDENCE.T working in Google Sheets?
CONFIDENCE.T runs in Google Sheets, but our executed cases show it does not match
Excel’s documented behavior on every input (the failing cases are listed on this page). If a
formula that behaves one way in Excel gives you a different answer in Sheets, compare your usage
against those cases before assuming your data is wrong.
Discovered quirks
-
=CONFIDENCE.T(0.05,1,1) on
Google Sheets returned
#NUM!, but the documented/expected
result is #DIV/0!.
Provenance
Excel documents: "If size equals 1, CONFIDENCE.T returns #DIV/0! error value." This is the one place the .T variant's error contract differs from CONFIDENCE.NORM's, which returns #NUM! only below size 1 and computes normally at size 1: with size 1 there are zero degrees of freedom for the t distribution; MISMATCH vs expected: expected '#DIV/0!', got '#NUM!'
-
=CONFIDENCE.T(0,1,50) on
LibreOffice Calc returned
#VALUE!, but the documented/expected
result is #NUM!.
Provenance
Excel documents: "If alpha <= 0 or alpha >= 1, CONFIDENCE.T returns the #NUM! error value."; MISMATCH vs expected: expected '#NUM!', got '#VALUE!'
-
=CONFIDENCE.T(0.05,0,50) on
LibreOffice Calc returned
#VALUE!, but the documented/expected
result is #NUM!.
Provenance
Excel documents: "If standard_dev <= 0, CONFIDENCE.T returns the #NUM! error value."; MISMATCH vs expected: expected '#NUM!', got '#VALUE!'
Executed test cases
Excel for the web (executed 2026-09-01 via OneDrive recalculation)
These values come from Excel for the web, not from desktop Excel. They are two different implementations of the calculation engine, and this run measured only the web one: the corpus was uploaded to OneDrive as .xlsx, recalculated by Excel for the web on open, and downloaded again for readback. Excel for the web is a rolling service with no pinnable version, so the run is identified by its date. Where a value here disagrees with the Expected column — which is Microsoft’s documentation of the desktop product — we cannot tell you whether the web engine diverges from the desktop one or the documentation is wrong about both, because we do not run desktop Excel.
| Formula | Description | Result | Expected | Verdict |
|---|---|---|---|---|
| =ROUND(CONFIDENCE.T(0.05,1,50),9) | Microsoft's documented worked example: 95% Student-t confidence half-width for a standard deviation of 1 and a sample of 50 | 0.284196855 | 0.284196855ProvenanceMicrosoft's page publishes this example's result as 0.284196855. Independently derived from the documented Student-t half-width t_(1-alpha/2, size-1) * standard_dev / sqrt(size): scipy.stats.t.isf(0.05/2, 49) = 2.0095752371292397 on size-1 = 49 degrees of freedom, so 2.0095752371292397 * 1 / sqrt(50) = 0.2841968554957299 -> 0.284196855 at 9 dp. The t multiplier is visibly larger than the normal 1.95996 of CONFIDENCE.NORM, which is what distinguishes the two functions |
Matched |
| =ROUND(CONFIDENCE.T(0.05,1,50.9),9) | A non-integer sample size, which the documentation says is truncated | 0.284196855 | 0.284196855ProvenanceExcel documents "If size is not an integer, it is truncated", so 50.9 must behave exactly as 50. Independently checked that this discriminates: a genuine size of 50.9 (49.9 degrees of freedom) would give 0.281545 |
Matched |
| =CONFIDENCE.T(0.05,1,1) | A sample size of exactly 1 | #DIV/0! | #DIV/0!ProvenanceExcel documents: "If size equals 1, CONFIDENCE.T returns #DIV/0! error value." This is the one place the .T variant's error contract differs from CONFIDENCE.NORM's, which returns #NUM! only below size 1 and computes normally at size 1: with size 1 there are zero degrees of freedom for the t distribution |
Matched |
| =CONFIDENCE.T(0,1,50) | A zero significance level | #NUM! | #NUM!ProvenanceExcel documents: "If alpha <= 0 or alpha >= 1, CONFIDENCE.T returns the #NUM! error value." |
Matched |
| =CONFIDENCE.T(0.05,0,50) | A zero standard deviation | #NUM! | #NUM!ProvenanceExcel documents: "If standard_dev <= 0, CONFIDENCE.T returns the #NUM! error value." |
Matched |
| =CONFIDENCE.T("abc",1,50) | A non-numeric alpha argument | #VALUE! | #VALUE!ProvenanceExcel documents: "If any argument is nonnumeric, CONFIDENCE.T returns the #VALUE! error value." |
Matched |
Google Sheets (executed 2026-08-31 via Drive import)
Google Sheets is a rolling service with no pinnable version, so this run is identified by its date. The corpus was imported to Drive as .xlsx, recalculated by Sheets, and exported back for readback.
| Formula | Description | Result | Expected | Verdict |
|---|---|---|---|---|
| =ROUND(CONFIDENCE.T(0.05,1,50),9) | Microsoft's documented worked example: 95% Student-t confidence half-width for a standard deviation of 1 and a sample of 50 | 0.284196855 | 0.284196855ProvenanceMicrosoft's page publishes this example's result as 0.284196855. Independently derived from the documented Student-t half-width t_(1-alpha/2, size-1) * standard_dev / sqrt(size): scipy.stats.t.isf(0.05/2, 49) = 2.0095752371292397 on size-1 = 49 degrees of freedom, so 2.0095752371292397 * 1 / sqrt(50) = 0.2841968554957299 -> 0.284196855 at 9 dp. The t multiplier is visibly larger than the normal 1.95996 of CONFIDENCE.NORM, which is what distinguishes the two functions |
Matched |
| =ROUND(CONFIDENCE.T(0.05,1,50.9),9) | A non-integer sample size, which the documentation says is truncated | 0.284196855 | 0.284196855ProvenanceExcel documents "If size is not an integer, it is truncated", so 50.9 must behave exactly as 50. Independently checked that this discriminates: a genuine size of 50.9 (49.9 degrees of freedom) would give 0.281545 |
Matched |
| =CONFIDENCE.T(0.05,1,1) | A sample size of exactly 1 | #NUM! | #DIV/0!ProvenanceExcel documents: "If size equals 1, CONFIDENCE.T returns #DIV/0! error value." This is the one place the .T variant's error contract differs from CONFIDENCE.NORM's, which returns #NUM! only below size 1 and computes normally at size 1: with size 1 there are zero degrees of freedom for the t distribution |
Mismatch |
| =CONFIDENCE.T(0,1,50) | A zero significance level | #NUM! | #NUM!ProvenanceExcel documents: "If alpha <= 0 or alpha >= 1, CONFIDENCE.T returns the #NUM! error value." |
Matched |
| =CONFIDENCE.T(0.05,0,50) | A zero standard deviation | #NUM! | #NUM!ProvenanceExcel documents: "If standard_dev <= 0, CONFIDENCE.T returns the #NUM! error value." |
Matched |
| =CONFIDENCE.T("abc",1,50) | A non-numeric alpha argument | #VALUE! | #VALUE!ProvenanceExcel documents: "If any argument is nonnumeric, CONFIDENCE.T returns the #VALUE! error value." |
Matched |
LibreOffice Calc 25.8.7.3 (tested 2026-08-31)
| Formula | Description | Result | Expected | Verdict |
|---|---|---|---|---|
| =ROUND(CONFIDENCE.T(0.05,1,50),9) | Microsoft's documented worked example: 95% Student-t confidence half-width for a standard deviation of 1 and a sample of 50 | 0.284196855 | 0.284196855ProvenanceMicrosoft's page publishes this example's result as 0.284196855. Independently derived from the documented Student-t half-width t_(1-alpha/2, size-1) * standard_dev / sqrt(size): scipy.stats.t.isf(0.05/2, 49) = 2.0095752371292397 on size-1 = 49 degrees of freedom, so 2.0095752371292397 * 1 / sqrt(50) = 0.2841968554957299 -> 0.284196855 at 9 dp. The t multiplier is visibly larger than the normal 1.95996 of CONFIDENCE.NORM, which is what distinguishes the two functions |
Matched |
| =ROUND(CONFIDENCE.T(0.05,1,50.9),9) | A non-integer sample size, which the documentation says is truncated | 0.284196855 | 0.284196855ProvenanceExcel documents "If size is not an integer, it is truncated", so 50.9 must behave exactly as 50. Independently checked that this discriminates: a genuine size of 50.9 (49.9 degrees of freedom) would give 0.281545 |
Matched |
| =CONFIDENCE.T(0.05,1,1) | A sample size of exactly 1 | #DIV/0! | #DIV/0!ProvenanceExcel documents: "If size equals 1, CONFIDENCE.T returns #DIV/0! error value." This is the one place the .T variant's error contract differs from CONFIDENCE.NORM's, which returns #NUM! only below size 1 and computes normally at size 1: with size 1 there are zero degrees of freedom for the t distribution |
Matched |
| =CONFIDENCE.T(0,1,50) | A zero significance level | #VALUE! | #NUM!ProvenanceExcel documents: "If alpha <= 0 or alpha >= 1, CONFIDENCE.T returns the #NUM! error value." |
Mismatch |
| =CONFIDENCE.T(0.05,0,50) | A zero standard deviation | #VALUE! | #NUM!ProvenanceExcel documents: "If standard_dev <= 0, CONFIDENCE.T returns the #NUM! error value." |
Mismatch |
| =CONFIDENCE.T("abc",1,50) | A non-numeric alpha argument | #VALUE! | #VALUE!ProvenanceExcel documents: "If any argument is nonnumeric, CONFIDENCE.T returns the #VALUE! error value." |
Matched |
Docs & syntax
- Excel (desktop): official documentation
- Google Sheets: official documentation
- LibreOffice Calc: official documentation
Where CONFIDENCE.T behaves differently
- Google-only functions: what ports to Excel and LibreOffice, and what does not
Executed: 47 functions Google documents and neither Microsoft nor LibreOffice does, 189 cases, 183 of them #NAME? in LibreOffice on all four pinned builds after five- and nine-spelling probes. QUERY and ARRAYFORMULA do not port; the operator functions do exactly; REGEXMATCH, REGEXTEST and REGEX are three different functions with three regex flavours.