The typical site contacts 7 third-party domains

LCP INP CLS

At a glance the headline numbers for Third-party domains

How many distinct third-party domains the page contacts.

on the typical site

half of sites sit at or below

1 in 4 sites exceed this

the top quarter

the heaviest 1%

the long tail

185,271

sites measured

phone field data

The typical site contacts 7 third-party domains. The heaviest 1% contact 35 or more.

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv

Distribution & median LCP site count and median LCP at each level of third-party domains

0ms 750ms 1500ms 2250ms 3000ms

2.5s

0 19193 38385

0 1 2 3 4 5 6–8 9–11 12–15 16–21 22–29 >p98

Good (≤2.5s) Needs improvement Poor (>4s) Site count

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv

Passing LCP by third-party domains which level passes the LCP most often

Third-party domainsSitesPassing LCPLCP

1 14,713 88% 1.3s

2 18,836 84% 1.4s

3 14,620 84% 1.5s

4 14,491 83% 1.5s

5 13,597 82% 1.5s

6–8 38,385 81% 1.6s

9–11 28,572 81% 1.6s

12–15 20,596 80% 1.7s

16–21 12,368 78% 1.7s

22–29 5,573 77% 1.8s

>p98 3,515 79% 1.8s

Good Needs Improvement Poor Faded rows: under 100 sites

Third-party domains 7. p75 11. p99 35. At the low end (1): LCP 1.3s. At the high end (>p98): LCP 1.8s. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv

Why this matters for the Core Web Vitals, and where to start fixing it

Third-party domains are a common Core Web Vitals issue. First of all, each third-party domain needs a new connection. That means time is lost on a DNS lookup, a TCP handshake and a TLS negotiation. If you had served those resources from your main domain, the browser could have re-used the connection that is already open (that is why you want HTTP/3: one fast, re-usable connection for everything you control). When that domain serves a font or a stylesheet, the browser cannot render before the connection is ready. The connection setup delays the LCP.

Also, third-party resources are usually out of your control. They can become a SPOF (single point of failure) when their server is slow or down. They can also change in size or behaviour without your knowledge, and your Core Web Vitals change with them. Self-hosting fixes both problems at once. Preconnect only hides part of the connection cost.

How do third-party domains affect the Core Web Vitals?

Third-party domains correlate with the LCP. With a single third-party domain, 88% of sites pass the LCP. Among the sites with the most third parties, 79% do. The decline is gradual. There is no point where sites suddenly start failing.

The effect is bigger on CLS. With a single third-party domain, 94% of sites pass it. Among the sites with the most third parties, 79% do. Third parties inject ads, embeds and consent banners, and injected content moves the layout after the page looks done.

Go fix it Self-host Google Fonts → The case for limiting analytics and tracking scripts → Guide to resource prioritization →

Related signals Responsive image markup → Stylesheet loading mix → Image format mix → Images per page → Chrome field data from 189,915 sites, representing millions of real page loads · How we measured