A backlink (also called an inbound link or external link) is a hyperlink that originates on one website and points to a page on another. From your perspective, any link from someone else's site to yours is a backlink.
Why backlinks matter
Google's original insight — embodied in its PageRank algorithm — was that links function like citations in academic publishing. A page with many high-quality links pointing to it is more likely to be authoritative and useful than one with few or none.
Backlinks remain one of the top three ranking factors in Google's algorithm, alongside content relevance and technical performance. A single high-quality backlink from a reputable, topic-relevant site can move rankings more than dozens of low-quality links.
What makes a good backlink?
Not all backlinks are equal. The quality of a backlink depends on:
- Domain authority of the linking site — A link from a major news outlet or industry publication carries more weight than a link from a new, obscure site
- Relevance — A link from a site covering your topic area is more valuable than one from an unrelated site
- Anchor text — The clickable text of the link gives Google context about what the linked page is about
- Link placement — Links in the main content of a page carry more weight than links in footers or sidebars
- Dofollow vs. nofollow —
nofollowlinks instruct Google not to pass ranking credit;dofollowlinks (the default) do pass credit
How to earn backlinks
- Create content worth linking to — Original research, comprehensive guides, tools, and data attract natural links
- Digital PR — Getting covered by journalists and bloggers through press releases or expert commentary
- Guest posting — Writing content for relevant industry publications in exchange for an author bio link
- Broken link building — Finding broken links on relevant sites and suggesting your content as a replacement
What to avoid
Buying links, participating in link schemes, or using automated link-building tools violates Google's guidelines and can result in a manual penalty that removes your site from search results.
Related terms
- Technical SEO — technical optimisation category
- On-Page SEO — the complementary on-page category
- SEO — the broader context
