Third-party cookies make up 60% of every cookie set across the web, according to the HTTP Archive’s Web Almanac 2025, which crawled the top 1 million websites by Chrome User Experience Report ranking in July 2025. That share is not evenly spread: on the 1,000 most popular sites, it climbs to 78%. The gap between a typical site and a top-tier one comes down almost entirely to how many ad, analytics, and embed integrations a page is running.
If you publish a cookie policy, this is the number that decides how long your third-party disclosure list actually needs to be. A small site with one analytics tag looks nothing like a retailer running a dozen ad exchanges, even though both sites might set the same handful of first-party cookies.
What percentage of cookies on a website are third party?
About 60% of cookies found across the top 1 million websites are third party, versus 40% first party, based on the HTTP Archive’s Web Almanac, an annual measurement project that crawls the top 1 million sites ranked by Chrome User Experience Report popularity. In the July 2025 crawl, that split held at the aggregate level even though individual sites vary enormously, from a static blog with zero third-party cookies to a news site running dozens of ad and tracking integrations at once.
Figure 1: The overall first-party versus third-party split across the full 1-million-site sample. Source: HTTP Archive Web Almanac, July 2025 crawl.
The one-sentence version: for every 10 cookies a visitor picks up browsing the web, roughly 6 came from a domain other than the one in the address bar.
Does the third-party share change with how popular a site is?
Sharply. On the 1,000 most-visited websites, the third-party share rises to 78%, up from 60% across the full 1-million-site sample, per the same July 2025 crawl. The most-visited sites on the web skew heavily toward ad-supported publishers, retail marketplaces, and platforms running several analytics and advertising vendors simultaneously, and each vendor typically adds its own cookie.
| Scope | Third-party share | First-party share | Source |
|---|---|---|---|
| Top 1 million sites (overall) | 60% | 40% | HTTP Archive, July 2025 |
| Top 1,000 sites | 78% | 22% | HTTP Archive, July 2025 |
The skew shows up inside the distribution too, not just between popularity tiers. Looking at desktop cookie counts by percentile, the third-party count climbs far faster than the overall total as a site gets heavier:
Figure 2: Third-party cookie count by percentile. A site at the 90th percentile carries 20 times more third-party cookies than one at the 25th. Source: HTTP Archive Web Almanac, July 2025 crawl, desktop.
A site’s third-party count is a much better predictor of how “heavy” it is than its first-party count, since first-party growth stays comparatively modest across the same percentile range.
Is the split different between desktop and mobile?
Only slightly, and the gap is concentrated entirely on the third-party side. At the median, desktop pages set 7 first-party and 7 third-party cookies, an even split, while mobile pages set 6 first-party and only 4 third-party, according to the July 2025 crawl. The total median cookie count is 9 on both platforms, but mobile pages simply run fewer third-party scripts.
Figure 3: Median first-party (first bar) versus third-party (second bar) cookies by device. Source: HTTP Archive Web Almanac, July 2025 crawl.
For the full percentile breakdown behind these medians, including how the gap widens further into the tail, see our post on how many cookies the average website sets.
Mobile’s lighter third-party load is most likely a byproduct of leaner mobile layouts and slimmer ad stacks, not a mobile-specific privacy control, since neither Chrome nor Android blocks third-party cookies by default any differently than their desktop counterparts.
How do you tell whether a cookie is first party or third party?
The test is the domain that set the cookie, not what the cookie does. A cookie is first party when it is set by the same domain shown in the browser’s address bar, and third party when it is set by any other domain, typically an embedded ad tag, analytics script, social widget, or payment iframe loading content from elsewhere.
Figure 4: The determining test for classifying a cookie as first party or third party. Source: synthesized from HTTP Archive Web Almanac methodology notes, 2025.
This distinction matters for a cookie policy because most privacy laws treat the two differently. Under GDPR and ePrivacy, both categories generally require disclosure, but many US state laws focus enforcement specifically on third-party sharing and “sale” of data, which makes an accurate first-party-versus-third-party classification a compliance requirement, not just a technical curiosity.
Which companies set the most third-party cookies?
A small number of ad and analytics platforms account for a large share of the third-party cookies found across the web. Google’s DoubleClick advertising infrastructure sets a cookie on 33% of the top 1 million websites, per the HTTP Archive’s July 2025 crawl. Its IDE cookie alone appears on 35% of sites, and the related test_cookie shows up on 25%. Microsoft reaches 14% of sites through a combination of bing.com, clarity.ms, and linkedin.com domains.
| Vendor / cookie | Domain | Share of top 1M sites |
|---|---|---|
| Google (IDE cookie) | doubleclick.net | 35% |
| Google (DoubleClick network) | doubleclick.net | 33% |
| Google (test_cookie) | doubleclick.net | 25% |
| Microsoft (bing/clarity/linkedin) | bing.com, clarity.ms, linkedin.com | 14% |
Source: HTTP Archive Web Almanac, July 2025 crawl.
For a site owner, this concentration is useful news. The third-party disclosures that actually cover most of the web are a short, predictable list dominated by a handful of advertising and analytics vendors, not hundreds of long-tail trackers unique to each site. If you have not audited what your own ad tags and embeds are setting on your behalf, a Cookie Policy Generator built around that first-party versus third-party split is a faster starting point than reconstructing the list by hand.
Is the third-party share rising or falling year over year?
It is trending up, at least at the median. The 2024 Web Almanac crawl measured a desktop median of 5 third-party cookies (against 7 first-party, for a total of 10). By the July 2025 crawl, the desktop third-party median had risen to 7, matching first-party exactly, while the total median actually dropped slightly to 9.
Figure 5: Desktop median third-party cookie count across two annual crawls. Source: HTTP Archive Web Almanac, 2024 and 2025 crawls.
Year-over-year swings this small in a single median are worth treating as a directional signal rather than a hard trend line, since only two data points exist so far. What is consistent across both crawls is the shape of the underlying distribution: first-party counts grow modestly from the median into the tail, while third-party counts grow explosively, the pattern a site owner auditing their own cookie footprint should plan around.
What keeps the third-party share this high?
Advertiser demand for cross-site tracking has not gone away, even as individual browsers have restricted it. 49% of marketers said their marketing strategy still depended on third-party cookie data in Adobe’s 2024 global survey of 2,841 marketers across seven countries, and Google confirmed on April 22, 2025 that it would not deprecate third-party cookies in Chrome after years of planning to. Chrome remains the largest browser worldwide, which keeps the infrastructure that sets these cookies working for most of the web’s traffic.
Figure 6: Browser policy and cookie-composition milestones, 2020 to 2025. Sources: WebKit, Mozilla, HTTP Archive Web Almanac, Google Privacy Sandbox.
Cookie composition data and cookie consent behavior are two sides of the same picture; see our cookie consent accept-rate and banner data for what happens once a visitor actually responds to a banner covering these cookies.
The Bottom Line
Third-party cookies are not a shrinking category on the average website, they are the majority category. 60% of all cookies found across the web are third party, and that share rises to 78% on the sites with the most traffic. The gap between a light site and a heavy one is almost entirely a third-party story: first-party cookie counts grow modestly across the distribution, while third-party counts explode, concentrated in a short list of dominant vendors led by Google’s DoubleClick network at 33% site reach. For a site owner, the practical implication is that an accurate cookie policy has to name the vendors setting cookies on your behalf, not just the cookies your own code writes, and that list needs revisiting as ad tags and embeds change.
Frequently Asked Questions
What percentage of cookies on a website are third party? About 60% of all cookies found across the web are third party, versus 40% first party, according to the HTTP Archive’s Web Almanac 2025, which crawled the top 1 million websites in July 2025. On the 1,000 most popular sites, the third-party share climbs to 78%.
Does the third-party cookie share change with how popular a site is? Yes. The share rises from 60% across the full 1-million-site sample to 78% on the top 1,000 most-visited sites, per the HTTP Archive’s July 2025 crawl. Popular sites carry more ad, analytics, and embed integrations, and each one typically sets its own third-party cookie.
Are cookie counts different on desktop versus mobile? Only slightly at the median. Desktop pages split 7 first-party to 7 third-party cookies, while mobile pages split 6 to 4, per the HTTP Archive’s July 2025 crawl. Mobile pages generally load fewer third-party ad and analytics scripts.
Which company sets the most third-party cookies? Google, through its DoubleClick advertising infrastructure, sets a cookie on 33% of the top 1 million websites. Its IDE cookie alone appears on 35% of sites, and Microsoft’s bing.com, clarity.ms, and linkedin.com domains together reach 14%, per the HTTP Archive’s 2025 crawl.
Sources and References
- HTTP Archive. (2025). “Cookies,” Web Almanac 2025. Crawl of the top 1 million websites ranked by Chrome User Experience Report, July 2025.
- HTTP Archive. (2024). “Cookies,” Web Almanac 2024. Crawl of the top 1 million websites, June 2024.
- WebKit. (2020). “Full Third-Party Cookie Blocking and More.” Safari 13.1 / iOS 13.4 announcement, March 24, 2020.
- Mozilla. (2022). “Firefox Rolls Out Total Cookie Protection By Default To All Users Worldwide.”
- Adobe. (2024). “Brands Make Progress Weaning Off Third-Party Cookies, Yet Feel Less Prepared Than Ever for a World Without Them.” Global survey of 2,841 marketers across seven countries, published July 15, 2024.
- Google Privacy Sandbox. (2025). “Next steps for Privacy Sandbox and tracking protections in Chrome.” Published April 22, 2025.
Note: All figures verified as of September 2026. Cookie counts and vendor share shift as the HTTP Archive publishes each new annual crawl, so headline figures here are refreshed at least twice a year.
