A backlink is a link from one website to another. When Site A links to Site B, Site B gets a backlink. Google treats backlinks as votes of confidence — pages with more high-quality backlinks tend to rank higher, because links are one of the oldest and most studied ranking signals in search. Domain Authority explained in plain English. complete guide to what link building is.
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That’s the one-paragraph version. If you’ve ever wondered “what are backlinks and why does everyone in SEO talk about them?” — below is the full picture: what backlinks actually are, why they matter more than most other ranking factors, the different types you’ll encounter, and how to tell a valuable backlink from a useless one.
What Is a Backlink?
At its simplest, a backlink is any hyperlink on one website that points to a page on a different website. If a food blogger writes a recipe roundup and links to your cooking site, your site just earned a backlink.
You’ll also hear backlinks called inbound links or incoming links — all three terms mean the same thing. The “back” part just describes the direction: the link comes back to your site from somewhere else.
Here’s a concrete example. Imagine you publish a free budgeting spreadsheet. A personal finance blog writes about it and includes this sentence:
“If you want a head start, grab this free budgeting template — it’s the cleanest one I’ve found.”
That linked phrase “free budgeting template” is the anchor text, and the link itself is a backlink to your page. One link, one backlink. If ten different sites link to that page, you have ten backlinks (assuming each comes from a different page — which brings us to an important distinction I’ll cover later).
Backlinks are different from internal links (links between pages on your own site) and outbound links (links from your site pointing elsewhere). Only links coming in from other domains count as backlinks.
Why Do Backlinks Matter for SEO?
Backlinks matter because Google was literally built on them. In 1998, Larry Page and Sergey Brin published the PageRank paper at Stanford, introducing the idea that a page’s importance could be estimated from the quantity and quality of links pointing to it. That insight became Google — and while the algorithm has grown enormously more complex since, links remain one of the core ways Google judges authority.
You can check any site’s authority for free with our website authority checker.
Think of it this way: anyone can claim their page is the best resource on a topic. But when independent websites voluntarily link to it, that’s evidence other people agree. Google’s documentation on how Search works describes ranking as a process of weighing hundreds of signals — and links from other sites are among the signals that tell Google a page is trustworthy and worth surfacing.
The correlation between backlinks and rankings has been measured repeatedly. Ahrefs has published studies analyzing millions of pages showing that pages ranking at the top of Google consistently have more backlinks — and more linking domains — than pages ranking lower. Correlation isn’t causation, and plenty of other factors matter (content quality, search intent match, page experience), but the pattern is remarkably consistent: strong pages attract links, and links help strong pages rank.
There are two practical reasons backlinks carry so much weight:
- They’re hard to fake at scale. You control your own content completely, so Google discounts what you say about yourself. Earning a link from an independent site requires someone else’s effort and judgment — that’s a much harder signal to game.
- They measure real-world endorsement. Journalists cite sources they trust. Bloggers recommend tools they use. Researchers link studies they build on. Each link is a small editorial decision, and in aggregate those decisions map remarkably well onto what humans consider authoritative.
That said, backlinks are not magic. A page with a thousand spammy links will lose to a page with ten excellent ones. Google’s spam systems — including the long-running Penguin updates, now part of the core algorithm — are specifically designed to ignore or discount manipulative links. Quality has always mattered more than quantity, and the gap keeps widening.
Types of Backlinks
Not all backlinks work the same way. The most important distinction is whether a link passes ranking credit — but there are several other types worth knowing.
Dofollow Backlinks
A dofollow link is a normal link with no special attributes. It’s the default: when someone links to you without adding anything extra to the HTML, search engines treat it as an endorsement and may pass ranking credit (often called “link equity” or “link juice”) through it. These are the links SEOs care about most.
Nofollow Backlinks
A nofollow link carries a rel="nofollow" attribute telling search engines not to pass ranking credit. Google introduced nofollow in 2005 to fight comment spam. Common sources of nofollow links: blog comments, forum posts, Wikipedia, and many social media profiles.
Nofollow links still have value — they can send real referral traffic, build brand visibility, and diversify your link profile (a natural-looking profile has a mix of both). They just don’t directly boost rankings the way dofollow links do.
Sponsored and UGC Links
Google added two more link attributes to give webmasters finer control:
- rel=”sponsored” — marks links that are advertisements or paid placements. Google requires paid links to be marked this way; unmarked paid links violate its spam policies.
- rel=”ugc” — marks user-generated content links (forum posts, comments, Q&A answers). It tells Google the link wasn’t placed by the site’s editors.
Like nofollow, these attributes mean “don’t count this as an editorial vote.” In 2019, Google announced it would treat all three attributes as hints rather than strict directives — meaning Google may choose to count them in some cases — but in practice, editorial dofollow links remain the gold standard.
Editorial Backlinks
An editorial backlink is one a publisher gives freely because your content genuinely deserves it — a journalist citing your data, a blogger recommending your tool, a university linking your research. These are the hardest links to earn and the most valuable, because they’re the purest form of the “vote” Google is trying to measure. Everything in link building is ultimately an attempt to earn more of these.
Other Common Types
- Guest post links — links in articles you write for other sites. Legitimate when the content is genuinely useful; risky when done at scale purely for links.
- Resource page links — links from curated “helpful resources” pages. Earned by having a resource worth curating.
- Directory and profile links — links from business directories or profile pages. Fine in moderation from legitimate directories; worthless from spammy link farms.
- Image links — when someone embeds your image or infographic with a link back. The anchor text is the image’s alt text.
What Makes a Backlink “Good”?
Since quality beats quantity, it helps to know exactly what Google — and experienced SEOs — look at when judging a link. Four factors matter most.
Relevance
A link from a site in your niche counts more than one from an unrelated site. If you run a fitness blog, a backlink from a nutrition site is worth far more than one from a car dealership — even if the car site has higher authority. Relevance tells Google the endorsement comes from someone qualified to judge your content. Off-topic links at scale are also a classic footprint of link schemes, so relevance protects you as well as helps you.
Authority of the Linking Site
All else equal, a link from a well-established, trusted site passes more value than one from a brand-new blog. This is the core PageRank insight: a vote from an authoritative source counts more. Third-party metrics like Moz’s Domain Authority or Ahrefs’ Domain Rating try to estimate this, and while they’re useful for prioritizing outreach, remember they’re approximations — Google’s internal measures are what actually count.
Placement and Context
Where the link sits on the page matters. A link inside the main body of an article, surrounded by relevant text, is worth more than the same link buried in a footer, sidebar, or author bio. Editorial in-content links are the strongest signal because they represent a genuine content-level endorsement. Sitewide footer links — the same link repeated on every page of a site — are heavily discounted and can look manipulative.
Anchor Text
The clickable words of the link give Google context about what the linked page is about. Descriptive, natural anchor text (“free budgeting template”) helps; exact-match keyword anchors repeated across many links (“best cheap SEO services”) look engineered and can trigger spam filters. A healthy link profile has varied anchor text: branded terms, naked URLs, generic phrases (“click here”), and topical phrases in natural proportion.
The short version: a good backlink is an editorial, dofollow link from a relevant, trustworthy site, placed naturally inside real content, with sensible anchor text. Everything else is a weaker version of that.
Backlinks vs Referring Domains
You’ll often see two numbers reported side by side: backlinks (total links) and referring domains (unique websites linking to you). Ten links from ten pages on the same site equal ten backlinks but only one referring domain.
Referring domains is the more important metric. Google’s systems care far more about how many independent sites vouch for you than how many individual links you have — the first link from a new domain moves the needle; the fiftieth link from the same domain barely registers. I’ve written a full breakdown of how backlinks differ from referring domains if you want the details, including why tools report these numbers differently.
How to Get Backlinks
Earning backlinks is a discipline of its own — but the honest summary fits in a paragraph: create something worth linking to, then make sure the right people see it. The “something worth linking to” is usually original data, a genuinely useful free tool, an in-depth guide, or a unique perspective. The “right people” are journalists, bloggers, and creators in your niche who link to resources like yours.
Common legitimate approaches include digital PR (pitching data and stories to journalists), guest posting on reputable sites, broken link building (finding dead links and suggesting your content as a replacement), and creating linkable assets like free tools and original research. What doesn’t work long-term: buying links, automated spam, private blog networks, and any scheme where the link exists only because money changed hands.
If you want a method-by-method walkthrough, start with my guide on ways to check your backlinks — you can’t improve your link profile until you can see it — and keep an eye out for the upcoming deep dive on link-building strategies.
Frequently Asked Questions
Quick answers to the most common questions about what are backlinks and how they work:
What is a backlink in simple terms?
A backlink is a link from another website pointing to your website. Think of it as a recommendation: when a site links to you, it’s telling its visitors (and Google) that your page is worth visiting. The more quality recommendations you collect, the more Google trusts your site.
Do backlinks still matter for SEO in 2026?
Yes. Despite two decades of algorithm evolution, backlinks remain one of Google’s core ranking signals — they were the foundation of PageRank, and large-scale studies (including Ahrefs’ analyses of millions of search results) continue to show a strong correlation between backlink profiles and rankings. What has changed is how strictly Google evaluates link quality: manipulative links are ignored or penalized, while genuine editorial links still move the needle.
How many backlinks do I need to rank?
There’s no magic number — it depends entirely on your competition. A local plumber might outrank competitors with a few dozen good links; a national finance keyword might require thousands. The better question is “how many referring domains do the current top-ranking pages have?” — tools like Ahrefs’ free backlink checker can show you that, and your target is to earn a comparable profile of quality links, not to hit an arbitrary count.
What’s the difference between backlinks and referring domains?
A backlink is a single link; a referring domain is a unique website that links to you. If one site links to you ten times, that’s ten backlinks but one referring domain. Referring domains matter more because Google values endorsements from independent sources — the first link from a new site counts far more than additional links from a site that already links to you.
Can backlinks hurt my website?
Yes, if they’re manipulative. Links from spam networks, hacked sites, or obvious paid-link schemes can trigger Google’s spam systems — though in most cases Google simply ignores bad links rather than penalizing you for them. The exception is large-scale manipulation, which can lead to a manual action. If you spot genuinely toxic links pointing at your site, Google’s disavow tool exists for that — but use it sparingly, since most low-quality links are harmless noise.
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