Google Ads vs GA4: Which Numbers Should You Trust?

Your Google Ads dashboard shows 150 conversions. Your GA4 dashboard shows 132. Your client asks: "Which number is right?"

The short answer: GA4 is more accurate for counting conversions. But the full answer is more useful than that. We covered the basics in [why Google Ads and GA4 show different numbers](/blog/why-google-ads-and-ga4-show-different-numbers) — this guide goes deeper on which one to trust and when.

What Google Ads Actually Counts

Google Ads does not count what happened on your website. It counts what it claims credit for.

When someone clicks a Google ad and converts within 30 days, Google counts that as a conversion. It does not matter if the person also clicked a Facebook ad, opened an email, or came back organically three days later. Google claims it.

Google Ads also counts view-through conversions. If someone saw your ad (did not click) and later converted through a different channel, Google can still count it.

This is called attribution. Google Ads uses a last-click attribution model within its own ecosystem. It gives itself credit for any conversion that follows a Google ad click, even if the ad was not the real reason the person converted.

The result

Google Ads numbers are inflated compared to what actually happened. Not because Google is lying, but because it is measuring through a lens that favours its own platform.

What GA4 Actually Counts

GA4 counts events on your website. When someone completes a purchase, fills out a form, or signs up, GA4 records it. GA4 does not care how the person arrived. It just tracks what they did.

GA4 uses an event-based model. Every action is an event. Conversions are just events you have marked as important. There is no attribution, no credit assignment, no platform bias.

The result

GA4 numbers are closer to what actually happened. It is the closest thing to ground truth you have.

The Numbers Compared

Here is what the same data looks like across both platforms:

The key difference: Google Ads counts conversions it can claim credit for. GA4 counts conversions that happened.

Why Google Ads Numbers Are Higher

Three reasons Google Ads typically shows 10-15% more conversions than GA4:

1. Attribution overlap

Most customers interact with multiple channels before converting. They might click a Google ad, see a Facebook ad, open an email, then convert. Google Ads claims this conversion. So does Meta Ads. GA4 counts it once.

2. View-through conversions

Google Ads counts conversions from people who saw an ad but did not click. GA4 does not distinguish between ad viewers and everyone else. It just records the conversion.

3. Conversion window

Google Ads uses a 30-day click window and a 1-day view window by default. If someone clicks a Google ad and converts 25 days later through organic search, Google still claims it. GA4 does not care about attribution windows — it records events as they happen.

When To Trust Google Ads Numbers

Google Ads numbers are useful for one thing: measuring Google Ads performance.

If you want to know "how many conversions did my Google ads drive?", Google Ads gives you that answer. It is measuring its own contribution to your results.

Use Google Ads numbers when: - Evaluating campaign performance within Google Ads - Comparing Google Ads campaigns against each other - Optimising bids and budgets inside Google Ads - Reporting ROAS to justify Google Ads spend

Do not use Google Ads numbers when: - Reporting total conversions to a client (it will be inflated) - Comparing across platforms (each platform gives itself credit) - Determining actual website conversions (use GA4)

When To Trust GA4 Numbers

GA4 numbers are useful for one thing: counting what actually happened on your website.

Use GA4 numbers when: - Reporting total conversions to a client - Comparing performance across all ad platforms - Calculating actual CPA based on real conversions - Building client reports that need to be accurate

Do not use GA4 numbers when: - Evaluating a specific platform's contribution (GA4 does not attribute) - Optimising bids inside Google Ads (use Google Ads data for that)

The Right Way To Report

The mistake most agencies make: picking one number and presenting it as "the truth."

The right approach: present all numbers and explain the gap.

This table tells your client: 1. What each platform claims 2. How each platform measures 3. Which number to use for what purpose

Clients do not expect all platforms to agree. They expect you to explain why they do not.

Why GA4 Is The Benchmark

GA4 is the benchmark because it has no incentive to inflate numbers.

Google Ads wants you to spend more. More conversions = better ROAS = you increase budget. Meta Ads wants the same. Both platforms benefit from claiming more conversions.

GA4 does not sell ads. It does not care which platform brought the visitor. It just records what happened on your website. That makes it the most neutral, accurate source.

This does not mean GA4 is perfect. GA4 can miss conversions if tracking code is broken, if users block cookies, or if events are not configured correctly. But when GA4 is set up properly, it is the most reliable number you have. For a full reconciliation process, see [how to reconcile Google Ads and GA4 numbers](/blog/how-to-reconcile-google-ads-and-ga4-numbers).

Setting Up GA4 For Accuracy

GA4 is only accurate if it is set up correctly. Here is what to check:

1. Conversion events are marked correctly

In GA4, go to Admin > Events. Make sure your key actions (purchase, form_submit, sign_up) are marked as conversions. If they are not marked, GA4 will not count them.

2. GA4 tag is on all pages

Use Google Tag Assistant to verify the GA4 tag fires on every page, especially conversion pages (thank you pages, confirmation pages).

3. No duplicate events

If your GA4 tag fires twice on the same page, conversions will be double-counted. Check for duplicate tags in Google Tag Manager.

4. Cross-domain tracking is set up

If your conversion happens on a different domain (payment gateway, third-party form), GA4 needs cross-domain tracking to connect the sessions.

Frequently Asked Questions

Is GA4 more accurate than Google Ads for conversions?

Yes. GA4 counts actual website events without attribution bias. Google Ads counts conversions it can claim credit for through its attribution model. GA4 is closer to ground truth because it has no incentive to inflate numbers.

Why does Google Ads show more conversions than GA4?

Google Ads uses attribution models that credit conversions to ad clicks within a 30-day window. It also counts view-through conversions. GA4 counts events as they happen without attribution. The 10-15% difference is expected.

Should I use Google Ads or GA4 for client reports?

Use both. Show Google Ads numbers for platform performance, GA4 as the ground truth for actual conversions, and calculate the discrepancy percentage. Clients trust transparency over a single number.

Can GA4 miss conversions that Google Ads catches?

Yes. GA4 can miss conversions if tracking code is broken, if users block cookies, or if conversion events are not configured. Always verify GA4 setup before using it as your benchmark.

Present The Full Picture

ADsHisaab pulls data from Google Ads, Meta Ads, and GA4. It shows all three side by side, calculates discrepancy percentages automatically, and uses GA4 as the ground truth in every report.

Your clients see what each platform claims, what actually happened, and the gap between them.

Start your free trial at adshisaab.com