A backlink is a link from one website to another. If a gardening magazine links to your guide on pruning roses, you have earned a backlink. Search engines treat these links as signs that other people find your content useful, which makes them central to off-page SEO.
Why backlinks matter
Google’s founding idea, PageRank, was that a link is like a citation in an academic paper: pages cited by many respected sources are probably important. Twenty-five years later Google uses hundreds of signals, yet studies still consistently find a strong relationship between quality backlinks and higher rankings, especially for competitive queries.
Backlinks also send referral traffic and help search engines discover new pages.
What makes a backlink valuable?
- Relevance: a link from a site in your industry counts more than one from an unrelated site.
- Authority: links from sites with strong link profiles and real audiences carry more weight.
- Editorial placement: a link inside an article beats one in a footer, sidebar or comment.
- Traffic: a link people actually click is a strong sign it is real.
- Uniqueness: the first link from a new domain usually matters more than the tenth from the same site.
- Follow status: followed links pass the most value. See dofollow vs nofollow links.
Good vs bad backlinks
Good: a local newspaper covering your charity event; an industry blog citing your survey; a supplier listing you as a stockist.
Bad: links bought from a “guest post marketplace” with no real readers; sitewide footer links on unrelated sites; links from private blog networks; spammy directory and forum profiles. These breach Google’s spam policies and belong to black hat SEO.
How to get backlinks
The full methods are covered in our link building guide. In short: create content worth citing, tell relevant people about it, and build relationships with journalists, bloggers and partners.
How to check your backlinks
- Google Search Console: the Links report shows top linking sites and pages for free.
- Ahrefs, Semrush, Moz, Majestic: larger indexes, anchor text analysis and competitor comparisons.
Comparing your profile with competitors shows the gap you need to close. Third-party metrics such as domain authority help you prioritise.
Do spammy backlinks hurt?
Google says it ignores most spammy links automatically. You only need to act if you have a manual action or a clear history of paid link schemes. Our guide to toxic backlinks and disavowing explains when.
Frequently asked questions
How many backlinks do I need?
It depends on the competition. Compare the referring domains of the top three pages for your keyword.
Are backlinks still important with AI search?
Yes. AI systems rely on search indexes that weigh links, and brand mentions add further signals.
Related terms
See anchor text, guest posting and the SEO encyclopedia.
Mr. SEO
Mr. SEO is the webmaster at SEO TT - SEO tips and tricks, a publication about all things SEO related.