Share of switchers that lose their Google Analytics or Tag Manager tag, by new platform
| New platform | Lost GA/GTM | Sites with GA/GTM before |
|---|---|---|
| WooCommerce | 26.5% | 155 |
| Drupal | 18.1% | 94 |
| WordPress | 17.4% | 448 |
| Nuxt | 12.9% | 201 |
| Next.js | 10.8% | 1,328 |
| PrestaShop | 9.1% | 44 |
| Shopify | 9.0% | 1,378 |
| BigCommerce | 7.0% | 43 |
| Webflow | 4.5% | 156 |
| Magento | 0.0% | 86 |
| All switchers | 11.2% | 4,057 |
Source: PageSpeed Matters, Sept 2026. Homepage tags the month before vs the month after the switch; the all-switchers row includes platforms not listed separately.
Summary
A platform switch rebuilds the templates that carry a site's tracking code. If the Google Analytics or Google Tag Manager snippet is not added back, the new site launches without it, and the gap may not show until someone opens the reports.
We checked how often the tag goes missing. Of 4,057 top 1M sites that loaded Google Analytics or Google Tag Manager the month before a platform switch, 11.2% no longer loaded it the month after. The new platform a site moves to makes a much bigger difference than how popular the site is.
What we measured
We used HTTP Archive's monthly crawls of the top 1M sites from September 2024 to September 2026 to find platform switches. A site counts as a switcher when it ran on one platform for 3 or more months and then on a different platform for 3 or more months.
For each switcher we compared the tags found on the homepage the month before the switch with the month after. A site counts as losing the tag when Google Analytics or Google Tag Manager was found before and not after. Switches between WordPress and WooCommerce were excluded, as they usually reflect a change in detection rather than a real move.
These are homepage checks only. A site that moved its tags to server-side tagging also looks like a loss in this data, so the result means the tag was no longer detected on the homepage, not that the site stopped measuring traffic.
About one in nine switchers lost the tag
Of the 4,057 switchers that loaded Google Analytics or Tag Manager the month before the move, 11.2% no longer loaded it the month after. Most of those did not come back quickly: 9.8% were still missing the tag in both of the first two months after the switch.
That second number matters. If tracking really stopped on those sites, the gap falls right when the team most needs to compare traffic before and after the launch.
Site popularity makes little difference. 10.4% of 424 Top 100K sites and 10.8% of 37 Top 10K sites lost the tag, against 11.3% of 3,596 sites ranked below 100K. The Top 10K group is small, so read that figure with care. Bigger sites with bigger teams lose the tag about as often as everyone else.
11.2%
Share of top 1M sites with Google Analytics or Tag Manager the month before a platform switch where the tag was no longer detected the month after.
The new platform makes the biggest difference
Sites moving to WooCommerce lost their Google tag most often: 26.5% of 155. Drupal (18.1% of a smaller group of 94) and WordPress (17.4% of 448) followed.
Among the larger groups, moves to Shopify (9.0% of 1,378), Next.js (10.8% of 1,328) and Webflow (4.5% of 156) lost it least. None of the 86 sites that moved to Magento lost the tag in our data.
A likely reason is how the tag gets installed. On WordPress and WooCommerce, Google tags are usually added through a theme setting or a plugin, and a fresh install starts without that setup. Hosted platforms usually keep tracking settings in one place in the admin, which may make them easier to carry over.
Where the site came from matters too
Looking at the platform sites left gives a similar spread. 27.3% of 110 sites leaving Joomla dropped the tag, the highest share in the data. At the other end, 6.4% of 110 sites leaving BigCommerce and 6.6% of 318 leaving Next.js lost it.
Sites leaving Shopify (15.5%), PrestaShop (14.2%) and WooCommerce (13.7%) also lost the tag more often than average. Older or plugin-based setups may hide the tag in a template or extension that nobody lists when planning the move, which makes it easy to leave behind.
Ad pixels drop out even more often
Analytics is not the only tag at risk. Of 2,268 switchers that loaded the Facebook pixel before the switch, 25.5% no longer did the month after. That is more than twice the loss rate for Google Analytics and Tag Manager.
Ad pixels feed conversion tracking and audience building, so a missing pixel can quietly weaken ad performance while the campaigns keep spending. Like analytics, some of that loss may be sites moving the pixel to a server-side setup, which this homepage data cannot see.
What this means for your site
Treat tracking as a launch requirement, not a follow-up task. Before the switch, list every tag on the old site: analytics, Tag Manager containers, ad pixels and any consent setup that controls them. Then confirm each one on the new site before launch.
- Check the new site with Google Tag Assistant or your browser's network panel on launch day, on the homepage and on key templates.
- Watch real-time reports in Google Analytics for the first hours after launch.
- If you move to server-side tagging at the same time, document it so the change is not mistaken for a loss later.
- Recheck a week after launch, since template or plugin changes in the first days can remove a tag that was working.
Sources
- HTTP Archive monthly crawls of the top 1M sites, September 2024 to September 2026
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<p style="font:14px/1.5 system-ui,sans-serif">Source: <a href="https://www.pagespeedmatters.com/resources/data-studies/migration-analytics-loss">Migration Analytics Loss: 11.2% of Sites Drop Their Google Tag - PageSpeed Matters</a></p>
Frequently asked questions
How often do sites lose Google Analytics during a migration?
Of 4,057 top 1M sites that loaded Google Analytics or Tag Manager the month before a platform switch, 11.2% no longer loaded it on the homepage the month after, and 9.8% were still missing it in both of the first two months.
Which platform migrations lose tracking most often?
Moves to WooCommerce lost the Google tag most often (26.5% of 155), followed by WordPress (17.4% of 448). Moves to Shopify (9.0%), Next.js (10.8%) and Webflow (4.5%) lost it least.
Do ad pixels survive a website migration?
Less often than analytics. 25.5% of 2,268 switchers that loaded the Facebook pixel before the switch no longer loaded it on the homepage the month after.
How do I check that my tracking survived a migration?
List every tag on the old site before the switch, then confirm each one on the new site at launch with Google Tag Assistant or your browser's network panel, and watch real-time reports in Google Analytics for the first hours.
A tag inventory and a launch-day check keep your analytics and ad data continuous through a platform switch. Need help with this? See our website migration services.