Guide 160 · Events · GA4 + Tag Manager
The 25-parameter limit per event: count the parameters, keep the useful ones, drop the rest
An event can carry at most 25 parameters, and the limit is enforced at collection time with no warning in the interface: the 26th parameter is dropped and nobody is told. This guide audits a tag that carries 26 parameters, counts what it sends, and cuts one — so the parameter that matters is never the one that disappears.
After the cut, the tag sends 25 parameters and DebugView shows all 25 on the event, including the one that was being dropped — and the Events report stops showing the parameter as missing.
Download the reference: the 25-parameter limit reference (JSON) (2613 bytes, MD5 9b5f24f62601527f461c020a8a5072cc). It lists the worked example — a tag that sends 26 parameters, the one that is dropped, and the 25 that remain — the limit as Google states it, and the rule that automatically collected parameters count toward the total. The tag itself is not in the file: the audit is a count, not a container.
What you need
- The tag to audit. Here it is the
GA4 - quote_requestedtag, which has grown a parameter row per request over a year: a category, a name, an ID, a test note, and a dozen more. - The limit, as Google states it. An event can carry at most 25 parameters, and the automatically collected parameters count toward the total — not only the rows you added.
- A list of what the tag actually sends. The count comes from the tag's Event Parameters rows plus the automatic parameters; guessing the number is how the 26th row got added.
The worked example
The audit below counts a tag that sends 26 parameters. The one that is dropped is the least useful row on the tag: a test note nobody reads.
| Measure | Count |
|---|---|
| Parameters the tag sends | 26 |
| Parameters allowed per event | 25 |
| Parameters dropped | 26 - 25 = 1 |
| Parameters after the cut | 25 |
| Share of parameters dropped | 1 / 26 = 3.85% |
Those figures were recomputed here before publication: 26 minus 25 is 1 parameter dropped; 1 divided by 26 is 0.0385, so 3.85% of the parameters never arrive. The row that is dropped is the 26th one — the test note — because the limit is enforced in order and the last row over the line is the one that goes.
The trace
- List every parameter the tag sends. Open the tag in Tag Manager and write down every row under Event Parameters. Then add the parameters GA4 collects automatically — page_location, page_title, and the session parameters among them — because the 25 counts them too.
- Count the list. Add the rows and the automatic parameters together. If the total is 25 or fewer, the tag is inside the limit and the audit is done. If it is 26 or more, the excess is being dropped silently, and the next step decides which rows go.
- Rank the parameters by use. For each row, ask one question: does a report, an audience, or a key event use this parameter? A parameter with no consumer is a candidate to cut. The test note is the first to go: it was added for a one-day test and never removed.
- Cut the tag down to 25. Delete the rows that lose the ranking until the count, including the automatic parameters, is 25 or fewer. Save the tag. Do not add a new row to replace the deleted one in the same edit — that is how the total creeps back over the line.
- Check it in Preview and DebugView. Click Preview, enter the site URL, and click Connect. Fire the event. In Tag Assistant, the tag must appear under Tags Fired. Then open DebugView (Admin, then Data display, then DebugView), click the event, and confirm the parameter that was being dropped now shows in the list.
- Publish it as a version. Click Submit at the top right, select Publish and Create Version, name the version, and click Publish. The cut reaches visitors only after this step.
Dead ends
DEAD END — THE LIMIT IS SILENT. GA4 does not warn you when a parameter is dropped, and the tag keeps firing cleanly. The only sign is a parameter that never shows in DebugView and never appears in a report. If a parameter is missing, count first; do not rebuild the tag.
DEAD END — COUNTING ONLY THE ROWS YOU ADDED. The automatic parameters count toward the 25. A tag with 23 rows of its own is already over the limit once the automatic ones are added, and the last two rows are the ones that go.
DEAD END — CUTTING THE PARAMETER A REPORT USES. Deleting a parameter stops it from being sent, and the reports that used it go empty from that day on. Cut the rows nobody uses first, and check the Custom definitions list before deleting anything a dimension is registered for.
End state
One tag, 25 parameters or fewer, every row with a consumer. The event shows all its parameters in DebugView, and no parameter is dropped silently. Keep the count in the tag's version description — the next person who adds a row reads the count before they add the 26th.
Sources
- Analytics Help — [GA4] Collection and configuration limits — up to 25 event parameters per event; the limit counts automatically collected parameters; parameter names up to 40 characters and values up to 100 characters on a standard property
- Tag Manager Help — Set up Google Analytics events in Tag Manager — the GA4 Event tag and its event parameters
- Analytics Help — Monitor events in DebugView — Admin, then Data display, then DebugView; click an event to see its parameters
Checked 11 November 2026. The click paths above are the ones in Google's help and developer pages, opened 11 November 2026. No step in this guide was run inside a live Analytics property or a live Tag Manager container, because both need a Google sign-in and this site does not sign in as anyone. What was run: the reference file was validated structurally in Python 3.12.3 — it parses, the event is quote_requested, and the limit fields are present — and the count was recomputed: 26 - 25 = 1 parameter dropped; 1 / 26 = 3.85% of the parameters never arrive. Google moves menu items without warning; if a path on this page no longer matches, the linked help page is the current map.