Free Harmonic Centrality Checker for AI Visibility
Check harmonic centrality by measuring how central your website is within Common Crawl, an open web dataset used to train some AI models.
No signup required. Results in seconds.
Top 100 Websites by Harmonic Centrality
The top 100 websites by harmonic centrality are the most central sites on the web. Rankings come from Common Crawl's July to September 2026 web graph of 133 million domains.
We left out scripts, font hosts, link shorteners and CDNs, so you only see real websites. Click any website to check it.
Updated with each new Common Crawl release. Change compares harmonic rank with April to June 2026.
What Does Harmonic Centrality Mean?
Harmonic centrality means how close a website is to every other website on the web. It counts how many link clicks it takes to reach you from each site.
Websites a few clicks away from many others score high. Websites that are hard to reach score low.
Harmonic centrality is calculated from the shortest link path from every other website to yours. Each distance is inverted, then all of them are added up. A normalized score divides the total by n − 1, where n is the number of websites.
Why Does Harmonic Centrality Matter for AI Visibility?
Harmonic centrality matters for AI visibility because it shapes how much of your website Common Crawl collects.
Common Crawl is a free archive of the web that many AI models are trained on. It uses harmonic centrality as a crawl-priority signal. Common Crawl says sites with higher harmonic centrality are crawled more often.
More crawled pages means your website may appear more often in the datasets later used to train AI models.
That's a correlation, not a guarantee. Common Crawl itself notes that no direct link to AI citations has been proven.
How Common Crawl Uses Harmonic Centrality
Common Crawl uses harmonic centrality to decide how many pages to crawl from each website.
Think of it as a page budget. The more central your website, the bigger its budget.
The most central websites can get up to 25 million pages crawled. Websites in the long tail get about 3,000.
Common Crawl has ranked websites this way since 2017. It chose harmonic centrality because it's harder to game with spam links than PageRank.
Each subdomain has its own cap too: up to 150,000 pages for top domains and 2,500 for the long tail. Top domains can have up to 500,000 subdomains crawled, long-tail domains 12.
Brighter bars are Common Crawl's published limits. The middle follows its log curve, estimated by Rankavi.
Source: Sebastian Nagel, Common Crawl, "From Web Graphs to Prioritizing Web Crawls", OSSYM 2021 at CERN. Limits as of summer 2021.
How to Use the Harmonic Centrality Checker
To use the harmonic centrality checker, enter your domains and read the table. It takes a few seconds.
Enter your domains
Paste up to 20 websites, one per line. Full URLs are trimmed to the domain.
Read your rank and tier
See each website's harmonic centrality rank, how it compares with the whole web and its tier.
Open a row for details
See the estimated crawl budget, PageRank rank, referring domains and your rank history over time.
What Your Harmonic Centrality Results Mean?
Your harmonic centrality results show eight details for each website. Here's what each one means.
- Harmonic centrality rank
- Your position among over 133 million domains. #1 is the most central website on the web.
- Share of the web
- The share of all domains that rank at or above you, like Top 0.44%. Smaller is better.
- Tier
- A quick label for your rank, from Elite to Long tail.
- Strength (0 to 100)
- Your rank turned into a simple score on a log scale. Higher is more central.
- Estimated page budget
- Roughly how many of your pages Common Crawl samples per crawl, based on its published limits.
- PageRank rank
- A second ranking from the same link data, based on the classic PageRank formula.
- Referring domains
- Unique websites that link to you in the same web graph.
- Rank history
- Your strength in each Common Crawl release since July 2024. Hover a point to see that quarter's rank.
Harmonic Centrality vs PageRank
The main difference between harmonic centrality and PageRank is how they measure importance in a network.
Harmonic centrality measures how close a node is to other nodes through the shortest paths. PageRank measures importance based on incoming links and the importance of the nodes providing those links.
That's why the same website can rank very differently on each. A small shop with links from many niche blogs often ranks far better by harmonic centrality.
Rewards being easy to reach from many websites. Harder to game with link spam.
Rewards links from a few very strong websites. Easier to inflate with link networks.
Harmonic Centrality Tiers
Harmonic centrality tiers group ranks into six bands, so you can read your position at a glance.
How to Improve Your Harmonic Centrality
To improve your harmonic centrality, make your website easy to reach from as many other websites as possible.
- Get links from many different websites. Breadth beats depth. Ten links from ten websites shorten more paths than ten links from one.
- Get listed where the web connects. Directories, resource pages and industry hubs sit a few clicks away from many websites.
- Earn links from well-connected websites. A link from a central website brings you closer to everyone that website is close to.
- Don't block Common Crawl's crawler. If your robots.txt blocks CCBot, Common Crawl can't read your pages or your outgoing links.
- Keep links crawlable. Use plain HTML links. Links that only appear after JavaScript runs can be missed.
- Publish a sitemap. Common Crawl uses sitemaps to discover pages, always for top domains and sometimes for smaller ones.
Harmonic Centrality Checker: Frequently Asked Questions
Answers to common questions about harmonic centrality and the free checker.
Yes, with no signup and no email. You can check up to 20 domains per search.
From Common Crawl's domain-level web graph, July to September 2026 release. It ranks over 133 million domains by harmonic centrality.
Common Crawl publishes a new web graph about every three months. We load each release when it comes out.
It isn't in the web graph yet. That usually means no other website linked to it when Common Crawl last crawled.
It's relative. A rank inside the top 1 million puts you in the top 0.75% of all domains. That's strong for most businesses.
No. Domain Rating is Ahrefs' backlink score. Harmonic centrality measures how close you are to every website in Common Crawl's link graph.
Google hasn't said so. Harmonic centrality here is Common Crawl's own ranking, used to decide what it crawls.
OpenAI's GPT-3 paper says filtered Common Crawl made up 60% of its training mix. Newer models don't publish their training data.
Not by itself. Being crawled is only the first step. AI answers also draw on live search and on what articles say about you.
Only if you don't want your content in open datasets. Blocking it removes you from data that many AI models learn from.
Data source: Common Crawl domain-level web graph (July to September 2026 release), served from Rankavi's own link database. Estimated page budgets use the per-domain limits Common Crawl published in 2021 and are approximate.