FORECAST.ETS
Unsupported (not recognized)Category: Statistical · Last tested 2026-09-01
Real compatibility results for the FORECAST.ETS 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) | Inconclusive (no verdict published) |
| Google Sheets | No | Yes (Drive import, 2026-08-29) | Unsupported (not recognized) |
| LibreOffice Calc | No | Yes (25.8.7.3, 2026-07-29) | Supported, behaves as documented |
LibreOffice version history
We executed the same test cases under each LibreOffice release to show exactly when FORECAST.ETS’s support changed — not documentation claims, real results.
| LibreOffice version | Verdict | Tested |
|---|---|---|
| 24.2.0.3 | Supported, behaves as documented | 2026-08-29 |
| 24.8.7.2 | Supported, behaves as documented | 2026-08-29 |
| 25.2.0.3 | Supported, behaves as documented | 2026-08-29 |
| 25.8.7.3 | Supported, behaves as documented | 2026-07-29 |
Why isn’t FORECAST.ETS working in Google Sheets?
Google Sheets does not implement FORECAST.ETS: we imported the formula into
Sheets on 2026-08-29 and every case came back #NAME?
(unrecognized function). Sheets is a rolling service with no version to pin, so this is a
statement about the service on that date, and Google’s own
function list does not document it either. Rewrite the formula with a documented
Sheets equivalent — see the
Excel ↔ Sheets equivalents table.
#N/A for every case of the FORECAST.ETS family — the existence probes, the value assertions and the cases that expected #NUM! or #VALUE! alike, all from the same 20-point timeline that FORECAST and FORECAST.LINEAR compute correctly on in this very run. A single error returned uniformly across arguments, dataset and error class is not a family of calculation defects; it is the exponential-smoothing feature being absent from this application. The name resolves (an unrecognised name is #NAME? here), and the expected values come from Microsoft’s documentation of the desktop product, so the disagreement is between what the two applications ship. The executed values are published exactly as they came back and no verdict is drawn from them.
Every executed case is shown below with exactly what Excel for the web returned.
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 |
|---|---|---|---|---|
| =FORECAST.ETS(A7,B1:B6,A1:A6) | Existence probe: exponential-smoothing forecast of the next point of a rising series. The AAA algorithm's exact output depends on implementation internals, so we only assert the engine recognizes the function and returns a numeric value (not #NAME?) | #N/A | ProvenanceNon-deterministic across implementations by design (smoothing-parameter optimization differs); the key datum is whether the engine has FORECAST.ETS at all. Excel returns ~70 for this series. |
Inconclusive |
Google Sheets (executed 2026-08-29 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 |
|---|---|---|---|---|
| =FORECAST.ETS(A7,B1:B6,A1:A6) | Existence probe: exponential-smoothing forecast of the next point of a rising series. The AAA algorithm's exact output depends on implementation internals, so we only assert the engine recognizes the function and returns a numeric value (not #NAME?) | #NAME? | ProvenanceNon-deterministic across implementations by design (smoothing-parameter optimization differs); the key datum is whether the engine has FORECAST.ETS at all. Excel returns ~70 for this series. |
Error |
LibreOffice Calc 25.8.7.3 (tested 2026-07-29)
| Formula | Description | Result | Expected | Verdict |
|---|---|---|---|---|
| =FORECAST.ETS(A7,B1:B6,A1:A6) | Existence probe: exponential-smoothing forecast of the next point of a rising series. The AAA algorithm's exact output depends on implementation internals, so we only assert the engine recognizes the function and returns a numeric value (not #NAME?) | 70 | ProvenanceNon-deterministic across implementations by design (smoothing-parameter optimization differs); the key datum is whether the engine has FORECAST.ETS at all. Excel returns ~70 for this series. |
Ran OK |
Docs & syntax
- Excel (desktop): official documentation