Google Ads vs GA4 conversions: why the two Google numbers differ
By the HonestTag team ยท Published November 13, 2026
Google Ads and Google Analytics 4 are linked and both come from Google, yet they report different purchase counts for the same week, sometimes with decimals and sometimes a little lower a few days later, and you want to know which one is wrong.
Usually neither is wrong: Google Ads and GA4 count the same purchases under different rules, so one week of sales gives two numbers. Google Ads reports a purchase on the date of the ad click and only when a Google Ads interaction led to it, while GA4 reports it on the date of the purchase, and in GA4's own reports paid and organic channels can both receive the credit. Decimals come from data-driven attribution splitting one purchase across several interactions. To tell which rule makes your gap, compare Google Ads' conversions by conversion time with the GA4 purchases credited to Google Ads, then compare GA4's total with your Shopify orders.
What each report counts
Google describes the two as different tools. Google Ads conversion measurement counts conversions only from Google Ads sources. Google Analytics can include conversions from other sources too, which is why Google recommends it for tracking all the traffic on your website.
- GA4 key events. GA4 now calls the events you mark as important to your business key events, and an event must be a key event before it can be imported into Google Ads. GA4 credits each one to the channels in the shopper's path under the property's reporting attribution model. Data-driven is the model Google recommends.
- The Google Ads Conversions column. It counts your primary conversion actions only, under each action's counting method, and it may include modeled conversions where Google cannot observe all of them. Google says this column is generally used for bidding.
- The Google Ads All conversions column. It adds secondary actions, which are for observation only, view-through conversions and a few other sources. View-through conversions are not included in the Conversions column.
- A GA4 purchase imported into Google Ads. Once imported it is a Google Ads conversion, and the counting method applies to it too. Google says Analytics uses last click for every Google Ads conversion based on a key event, and only key events where Google Ads is the last non-direct click become Google Ads conversions, whatever model is selected in Ads. Google also says imported data can take up to 24 hours to appear, and history from before the import is not included.
- A purchase from a Google Ads tag. A purchase action fed by a Google Ads tag rather than by GA4 is credited by the action's own attribution model. Data-driven is the default for most conversion actions.
Why the two numbers differ
Google says differences between the two are common and can happen even with a correct setup. These are the rules behind them, and each leaves a mark you can read:
- The date. Google Ads reports a conversion on the date of the click that led to it, not the date of the purchase. GA4 reports it on the day it happened. Google's own example: a click on July 19 and a purchase on July 20 sit on July 19 in Google Ads and on July 20 in Analytics. Google Ads also reports conversions by conversion time, which Google says helps when comparing with Google Analytics or Shopify. A gap that shrinks when you read by conversion time is the date rule.
- Who gets the credit. In GA4's own reports, paid and organic channels can both receive credit by default. In Google Ads reports the default is Google paid channels only, and Google Ads reports a conversion only when an interaction from that Google Ads account led to it. A purchase whose path held an organic search, an email visit and an ad click can sit partly or wholly on another channel in GA4 and still count in Google Ads. A purchase imported from GA4 reaches Google Ads only when Google Ads was the last non-direct click.
- Decimals. Data-driven attribution splits the credit for one conversion across several interactions, and Google shows the parts as decimals like 0.33 or 0.50. It is the default model for most Google Ads conversion actions, and GA4 does the same in its reports, where the parts of one purchase add up to 1.0. Under that model, a total with decimals is not by itself a sign of a fault.
- Which column. The Conversions column holds primary actions only. All conversions adds secondary actions and view-through conversions. Google calls comparing one column with the other, or with Analytics, a frequent reason for gaps.
- How many per click. A Google Ads action set to count One records only one conversion per click, while GA4 counts each purchase event. A shopper who buys twice after one click is two in GA4 and one in Google Ads.
- How far back. A Google Ads conversion window runs from 1 to 90 days and its cookies expire 90 days after the click, while the Analytics cookie lasts up to 2 years. A purchase made after the Google Ads window, and within 2 years of the click, is recorded in Analytics but not in Google Ads. GA4's own lookback for purchases is 90 days by default, and can be set to 30 or 60.
- Invalid clicks, removed later. Google filters out some conversions from clicks it judges invalid when they are imported from Analytics. It also removes conversions it later finds came from invalid traffic, and Google says this can happen after they were first reported, so a past day can show a small drop over time.
- Time zones and timing. GA4 uses the property's time zone and Google Ads the account's, so a day's edges can fall in different places. Google asks you to allow 24 to 48 hours for processing between the two before comparing.
Several of these at once can open a wide gap. One merchant in the Shopify Community saw purchases attributed to Google Ads campaigns at 1,104 in GA4, against 226.09 imported purchases in Google Ads for the same month.
A worked example
The numbers below are made up to show the arithmetic. They are not from a store. A store takes 140 online orders in one week. Its primary Google Ads purchase action is fed by a Google Ads tag and uses data-driven attribution, and GA4 runs on its own tag. Its numbers for the week:
| Number | Week | What the step means |
|---|---|---|
| Shopify orders | 140 | What the store took |
| GA4 purchases, all channels | 118 | 22 orders the GA4 tag did not record |
| Google Ads Conversions, by click date | 52.4 | Google's own report of the week |
| Google Ads Conversions, by conversion time | 47.0 | 5.4 less: the date rule |
| GA4 purchases credited to Google Ads | 41.6 | 5.4 less: mostly the credit rule |
Read from the middle. 52.4 against 47.0 is the date rule: purchases dated to this week's clicks but made after it, less the purchases made this week from earlier clicks. 47.0 against 41.6 is mostly the credit rule: in GA4, organic search, email and other channels in the same paths took part of the credit, while Google Ads shared each purchase only among its own ad interactions. Google says differences can remain even by conversion time, from attribution models, lookback windows and how each platform processes data, so this step holds those too. Neither Google number starts from the 140 orders: each counts the purchases its own tag recorded, and Google Ads may add conversions it models. Had the store imported GA4's purchase instead, Google Ads would hold only the purchases where Google Ads was the last non-direct click in GA4.
Now suppose a later week shows Google Ads by conversion time at 30.2 while GA4's purchases credited to Google Ads hold near 41, and Shopify orders hold. The date rule is out of the picture, so the change is on the Google Ads side: which actions sit in the Conversions column, a counting method, conversions Google removed, or the Google Ads tag itself. If instead GA4's total fell against Shopify orders, the change is in what the GA4 tag recorded, which GA4 revenue vs Shopify covers.
Read Google's claims against your own orders. HonestTag counts the new customers Google Ads brought from your Shopify orders and shows them beside what Google claims, whichever date or credit rule each Google report uses.
What this means
Much of the gap between Google Ads and GA4 is how the two count, but Google also lists tag setup among the causes, so read it in steps before calling it normal. Google Ads by click date against by conversion time is the date rule. By conversion time against GA4's purchases credited to Google Ads is mostly the credit rule, with lookback windows, counting and Google's processing in it too. GA4's total against your Shopify orders is what the GA4 tag recorded. The step that changes tells you the cause. A gap that opens on one date while your orders hold points to a change on that date.
The cost is in what you decide from it. And both Google reports grade credit with Google's own rules: neither tells you how many new customers an ad actually brought.
HonestTag starts from your Shopify orders instead: on the free Mirror plan, The Gap shows what Google Ads claims beside the new customers whose first recorded ad click or ad-tagged link was Google's, counted whole, under one stated rule.
How HonestTag helps
HonestTag counts your side of the comparison from your Shopify orders, so the date and credit rules that separate the two Google reports do not change that count.
- On the free Mirror plan, The Gap puts the conversions Google Ads claims beside the new customers whose first recorded ad click or ad-tagged link was Google's, counted from your own orders over the 14 days up to yesterday. Your side of that comparison comes from orders, not from GA4 or a Google credit rule. The Mirror plan sends no purchases to any ad platform.
- Whole customers, one stated rule. HonestTag uses one model, first click on new customers, so each new customer counts once, for the platform of the first ad click or ad-tagged link it recorded, with no fractions.
- On paid plans, one order with one ID in both Google tools. HonestTag can send each verified web purchase to Google Ads and to your GA4 web stream from its server, within your plan's limit on destinations at once, with the Shopify order ID as the transaction ID. In Google Ads it goes to HonestTag's own actions, which are secondary by default and do not change your bidding unless you choose. By default, in GA4 it goes as HonestTag's own ht_purchase event, which does not add to GA4's purchase and revenue reports.
- On paid plans, The Gap shows Google's platform-reported purchases next to the purchases HonestTag sent it, and order proof shows for each order what each platform was sent, or why it was not.
Every field sent is in Connect Google Ads and the GA4 connection guide.
Install HonestTag free from the Shopify App Store and see on the Mirror plan what Google Ads claims beside the new customers your own orders say it brought.
Frequently asked questions
Should Google Ads conversions match GA4?
Not exactly. Google says differences between the two are common even with a correct setup. Google Ads dates a purchase by the ad click and counts only purchases an interaction from that account led to, while GA4 dates it by the purchase, and in GA4's own reports organic channels can receive the credit too. The closest pair is Google Ads conversions by conversion time against the GA4 purchases credited to Google Ads, on the same dates.
Why does Google Ads show conversions with decimals?
Data-driven attribution, the default model for most Google Ads conversion actions, splits the credit for one conversion across several ad interactions. Google shows the parts as decimals like 0.33 or 0.50, so a total with decimals is normal under that model.
Why did a past day's Google Ads conversions go down?
Google removes some conversions when it detects they came from invalid traffic or invalid clicks, and it says this can happen after they were first reported, so the count can show a small drop over time. A large fall that GA4 and your Shopify orders do not share has another cause.
Which number should I trust for my sales?
Your Shopify orders. Both Google numbers are Google's reading of which purchases its ads or your channels earned. Read them against your orders for the same days, not against each other alone.
Does HonestTag change my Google Ads numbers?
Not on the free Mirror plan, which sends Google no purchases. On paid plans, HonestTag's own Google Ads actions are secondary by default, so they report in All conversions and do not change your bidding unless you choose.
Sources
- Google Ads Help: Create conversions from Google Analytics events in Google Ads, read November 13, 2026
- Google Ads Help: Data discrepancies: Factors and troubleshooting, read November 13, 2026
- Google Ads Help: Understand your conversion tracking data, read November 13, 2026
- Google Ads Help: About "All conversions", read November 13, 2026
- Google Ads Help: About attribution models, read November 13, 2026
- Google Analytics Help: Conversions vs. key events in Google Analytics, read November 13, 2026
- Google Analytics Help: Select attribution settings, read November 13, 2026
- Google Analytics Help: Key event attribution models report, read November 13, 2026
- Google Analytics Help: Change the reporting attribution model for key events, read November 13, 2026
- Shopify Community: Data Discrepancy Between GA4 & Google Ads (merchant thread, October 12, 2023), read November 13, 2026
- Shopify Community: Google ads conversions dropped (merchant thread, December 1, 2025), read November 13, 2026
- HonestTag: the conversion actions HonestTag creates in Google Ads
- HonestTag: GA4 connection guide
- HonestTag pricing and plan limits
Related reading: GA4 revenue vs Shopify sales, Google Ads conversion tracking on Shopify, ad platform purchases vs Shopify orders, and attribution models, compared.
Read Google's claims against your own orders
HonestTag counts the new customers Google Ads brought from your Shopify orders and shows them beside what Google claims, whichever date or credit rule each Google report uses.
- Feed your ads a clean signal. On paid plans, the platforms you send to get each verified purchase, new customers marked as new once confirmed.
- Catch the sales your pixels miss. On paid plans, purchases are sent from your Shopify orders, server to server.
- Know what to scale. From the Truth plan, a weekly scale, hold or cut call when the data supports one, and on every paid plan, proof behind every attributed order.
- Start free. The free Mirror plan puts Google Ads and Meta claims beside your orders. Keep your current tracking while you look.