What to Do If GA4 Starts Sending Duplicate Events After Setting Up Conversions

Lately, more and more people have been actively switching to GA4, and I keep seeing the same issue come up in various groups and chats:

“I set up an event for GA4, everything looked fine at first — but after marking it as a conversion, GA4 started sending duplicate events.”

If you’re facing a similar issue, this article is for you.

• How to fix it?
• Why was the previous setup a mistake?

How to fix it?

Since the #AnalyticsTips series is about quick answers, let’s start with the solution. Go to Admin > Events, and choose Create event.

Most likely, you’ll find the event that’s causing the duplicates there.

Open it and click Delete in the top right corner.

Now try sending the event again — the duplicates should be gone.

Why was the previous setup a mistake?

Let’s clarify one important point first:

In GA4, there is only one way to create a conversion — by enabling the toggle next to an event.

And there are two ways to enable this toggle:

1. On the Events tab by toggling Mark as key event (this works only if the event already has data within the selected time range).
2. On the Key events tab by clicking New key event and entering the event name (in this case, Google will activate the toggle even if no data has yet been collected for the event).

So, to create a conversion in Google Analytics 4, you simply need to:

• Send the event (either via developer implementation or through GTM)
• Enable the toggle for that event

The Create event feature allows you to define a new custom event based on conditions within events already sent to GA4 — either by a developer or via GTM.

For example, you can create a new event that isolates a specific form submission out of all form submission events on the site.

However, many GA4 users mistakenly believe that this is the place to create conversions, so they define custom events like the one shown in the screenshot — but GA4 interprets this setup differently than the user expects.

Here’s a visual I created to show what commands you’re actually giving GA4 when setting it up this way:

Of course, this isn’t the only reason duplicates occur in GA4 — but it’s definitely one of the most common mistakes.

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