Free backlink checker for any website
See which websites link to any site – .co.uk, .com or any other ending – how strong those links are, and which websites link to your competitor but not to you. No account, no email.
- No cost
- No sign-up
- No email
- No Google sign-in
- No subscription
- No limits for normal use
What the backlink checker shows
Websites linking to you
How many different websites link to a site, counted once each – the headline number most SEO tools use.
Your strongest links
The 50 strongest linking websites, strongest first, each with a link strength score.
The link gap
Add a competitor to see the strong websites that link to them but not to you – your best list of link prospects.
Where does the link data come from?
From Common Crawl, a non-profit that crawls billions of web pages every month and publishes a free map of which websites link to which. Each quarter XKey takes the newest map – over 130 million websites and 2 billion links – and builds an index of every website that's linked to, whatever its ending. That's the same kind of data the big paid tools build with their own crawlers.
What is link strength?
A score from 0 to 100 based on how many different websites link to a site, on a logarithmic scale – so going from 10 to 100 linking websites moves the score as much as going from 1,000 to 10,000. The most-linked website on the web scores 100. A local business with a few dozen good links typically scores 15–30; national newspapers and government sites score 60 and above. It's comparable to Ahrefs' Domain Rating or Moz's Domain Authority in spirit, but it's our own calculation, so the numbers won't match theirs.
How do I use the link gap?
Work down the list and ask why each website links to your competitor. Usually it's one of a handful of reasons: a supplier or manufacturer listing stockists, a trade body or directory, a local club or charity they sponsor, a news story, or a genuinely useful guide on their site. Most of those are open to you too. Never buy links – Google treats paid links as spam, and our local SEO checklist covers the honest ways to earn them.
What it can't tell you
- Only the 50 strongest linking websites. The count of linking websites is complete, but the list (and the link gap) shows each site's 50 strongest, to keep lookups fast and free.
- Not every link on the web. Common Crawl visits billions of pages but not all of them, so small or new sites may show fewer links than they really have – and links added in the last few months won't appear until the next quarterly update.
- Websites, not individual pages. It counts linking websites and shows which ones; it doesn't list the exact page each link is on, its anchor text or whether it's nofollow. Subdomains count as their main site, so blog.example.com is looked up as example.com.
Frequently asked questions
Is this backlink checker really free?
Yes. No sign-up, no email and no subscription, with only a fair-use limit to stop bots. The data is public, and XKey builds the index itself, so there's nothing to upgrade to.
How often is the backlink data updated?
Every three months, when Common Crawl publishes its next web graph. The months the data covers are shown under every result.
Why does my site show no backlinks?
Either no other website links to it yet, or Common Crawl hasn't crawled the pages that do. New sites often take a few months to appear. Getting listed on a few genuine local directories and suppliers' sites is the quickest honest way to start.
Can I check a competitor's backlinks?
Yes – any website, UK or not. Put your site in the first box and theirs in the second to see the websites that link to them but not to you.
Related guides
How to get backlinks
How to get backlinks without buying them: 12 honest ways small businesses earn links from suppliers, local groups, the press and useful content.
What is domain authority?
Domain authority explained in plain English: what the score means, whether Google uses it, how to check yours free and honest ways to increase it.
Competitor SEO analysis
A free, step-by-step competitor SEO analysis: who really competes with you on Google, what their pages do better, and where their links come from.
Business directory listings
Which UK business directories are worth listing on for local SEO, why consistent name, address and phone details matter, and which listings to skip entirely.
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Run a free SEO check now
About 50 checks covering Google, AI search, speed, security and local SEO. No sign-up.
Want the fixes done for you? XKey is made by IceWork, a web studio in Blackpool. IceWork builds fast, search-ready websites – a 3-page site including domain and a year's hosting is £350 all in.