WordPress homepages calling admin-ajax.php on load (Sept 2026, top 1M)
| Group | Call admin-ajax.php | Homepages |
|---|---|---|
| Top 10K | 4.2% | 759 |
| Top 100K | 7.4% | 8,138 |
| Rest of top 1M | 13.6% | 114,603 |
| With WooCommerce | 27.4% | 21,924 |
| Without WooCommerce | 10.0% | 101,576 |
| All WordPress | 13.1% | 123,500 |
Source: PageSpeed Matters, Sept 2026. WordPress means homepages requesting any /wp-content/ or /wp-includes/ file.
Summary
admin-ajax.php is the WordPress file that themes and plugins call when they need fresh data from the server without reloading the page. It is meant for things a visitor does: adding to cart, filtering a list, sending a form. When a page calls it during load, before the visitor has done anything, every page view sends extra work to PHP and the database that page caching usually cannot absorb.
We checked how many WordPress homepages in the top 1M do this. 13.1% (16,171 of 123,500) call admin-ajax.php on load. WooCommerce stores do it far more often, big sites rarely do, and homepages that make the call pass Core Web Vitals far less often.
What we measured
We looked at the HTTP Archive crawl from September 2026, mobile, which covers the top 1M sites by Chrome traffic, and at every request each homepage made. The crawl loads each page without clicking anything, so any admin-ajax.php request it records happened without visitor interaction.
A homepage counts as WordPress when it requests any file from /wp-content/ or /wp-includes/, which gives 123,500 homepages. A homepage is flagged when any of its request URLs contains admin-ajax.php. If WordPress is instead identified from the crawl's own platform labels, the rate is 14.0%. Core Web Vitals pass rates use Chrome UX Report field data where it is available.
Two limits apply. Some of these calls are lightweight and cost little. And the Core Web Vitals gap is a correlation: it does not prove that the call itself makes the page slower.
More than one in eight WordPress homepages call it on load
Of 123,500 WordPress homepages in the top 1M, 16,171 call admin-ajax.php while the page loads. That is 13.1%.
Each of those calls goes back to the server and starts WordPress again to answer it. Page caches usually store the HTML of a page, not the answers to these background requests, so the work repeats on every visit. On a busy site or modest hosting, that is load the server has to carry for visitors who have not asked for anything yet.
13.1%
Share of top 1M WordPress homepages (16,171 of 123,500) that call admin-ajax.php while the page loads, before any visitor interaction.
WooCommerce stores do it far more often
Stores make this call far more often than other WordPress sites. 27.4% of 21,924 WordPress homepages running WooCommerce call admin-ajax.php on load, against 10.0% of 101,576 WordPress homepages without it.
Stores likely have more reasons to fetch live data: cart contents, stock, prices for a logged-in customer, product filters and popups that react to what is in the cart. Plugins that add those features often use admin-ajax.php to get it, and some fire the request on every page view whether the visitor needs it or not.
Big sites rarely do it
The habit is much less common at the top. 4.2% of 759 Top 10K WordPress homepages call admin-ajax.php on load, and 7.4% of 8,138 Top 100K homepages do. In the rest of the top 1M the rate is 13.6% of 114,603 homepages.
Large sites tend to have developers who move background requests to faster endpoints, delay them until a visitor acts, or remove them. Busy sites also feel the server cost sooner, which gives them a reason to make the change.
Homepages that call it pass Core Web Vitals far less often
36.8% of the 14,663 homepages that call admin-ajax.php on load and have Chrome UX Report data pass Core Web Vitals. Among the 93,159 homepages that do not make the call, 50.3% pass.
That gap is a correlation, not proof of cause. A homepage that calls admin-ajax.php on load is often one that runs several feature-heavy plugins, and those plugins usually bring scripts, styles and widgets of their own. The call is best read as a sign that a page is doing a lot of work on load.
What this means for your site
Start by checking whether your homepage makes the call. Open your browser's developer tools, go to the network panel, reload the page without touching anything, and filter for admin-ajax.php.
If you see requests:
- Find which plugin or theme feature sends them. The request usually includes an action name that points to it.
- Ask whether that feature needs live data before the visitor does anything. Many popups, counters and cart widgets can wait for a click or scroll.
- Where the data is needed, ask the plugin developer or your developer whether it can use a cached or lighter endpoint.
- Recheck your server response times and Core Web Vitals after each change.
Sources
- HTTP Archive crawl of the top 1M sites by Chrome traffic, September 2026, mobile
- Chrome UX Report (CrUX) field data, September 2026
- Chrome UX Report documentation: https://developer.chrome.com/docs/crux
Embed this research
Paste this on your site to embed the chart. It links back to the source automatically.
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<script>window.addEventListener("message",function(e){if(e&&e.data&&e.data.psmEmbed==="admin-ajax-php-statistics"&&e.data.height){var f=document.getElementById("psm-admin-ajax-php-statistics");if(f){f.style.height=e.data.height+"px";}}});</script>
<p style="font:14px/1.5 system-ui,sans-serif">Source: <a href="https://www.pagespeedmatters.com/resources/data-studies/admin-ajax-php-statistics">admin-ajax.php Statistics: 13.1% of WordPress Homepages - PageSpeed Matters</a></p>
Frequently asked questions
How many WordPress sites call admin-ajax.php on page load?
13.1% of top 1M WordPress homepages (16,171 of 123,500) call admin-ajax.php while the page loads, before the visitor does anything.
Do WooCommerce stores call admin-ajax.php more often?
Yes. 27.4% of WordPress homepages running WooCommerce call admin-ajax.php on load, against 10.0% of those without it, likely because stores fetch more live data such as cart contents and filters.
Does admin-ajax.php slow down WordPress?
Homepages that call it on load pass Core Web Vitals 36.8% of the time, against 50.3% for those that don't. That is a correlation; the call often comes alongside other plugin weight.
How do I check if my site calls admin-ajax.php on load?
Open your browser's network panel, reload the homepage without clicking anything, and filter for admin-ajax.php. Any request you see was made before visitor interaction.
Background requests that fire on every page view can usually be delayed, cached or removed without losing the feature behind them. Need help with this? See our WordPress support services.