What Are Backlinks? Everything You Need to Know (2026)

Let’s cut straight to it.

A backlink is a link from one website to another. When Site A links to Site B, Site B has earned a backlink from Site A.

That’s the simple definition. But the reason backlinks matter — and the reason entire SEO agencies are built around acquiring them — is considerably more interesting.

3.8xMore backlinks: Google’s #1 result vs pages ranking in positions 2–10Backlinko study of 11.8 million Google search results

That single number explains why backlinks are one of the most-discussed topics in SEO. And in 2026, despite thousands of algorithm updates and the rise of AI-powered search, they remain one of Google’s three most important ranking factors.

This guide covers everything: what backlinks actually are, how they work, why some are worth 100x more than others, and what’s changed about them in the AI search era.

Already know the basics? Jump ahead: 15 Link Building Strategies That Actually Work in 2026 | How to Do a Backlink Audit | Best Link Building Tools in 2026.

What Is a Backlink? (The Real Explanation)

In its most technical form, a backlink is an HTML hyperlink on one webpage that points to a URL on a different domain.

What a backlink looks like in HTML:<a href=”https://linkbuildingjournal.co.uk/what-are-backlinks”> The Complete Backlinks Guide </a>

When you click that link, you travel from one site to another. But to Google’s crawlers, that same link carries a signal: the page linking out has decided that the destination is worth referencing.

That editorial decision is the signal. And it’s the reason backlinks have been at the heart of Google’s algorithm since the very beginning.

Where the Idea Came From: PageRank

In 1998, Google’s founders Larry Page and Sergey Brin published a paper introducing PageRank — an algorithm that ranked web pages based on how many other pages linked to them, and how authoritative those linking pages were.

The core insight was brilliant in its simplicity: if a lot of credible websites link to a page, that page is probably worth reading. Links were votes. Pages with more high-quality votes ranked higher.

Nearly three decades later, the principle is still intact. The algorithm is exponentially more sophisticated. But the vote metaphor still holds.

Google co-founder Larry Page on PageRank: ‘PageRank reflects our view of the importance of web pages by considering more than 500 million variables and 2 billion terms.’ The link graph remains the foundational structure underpinning that calculation.

Why Backlinks Matter for SEO in 2026

You might have heard that backlinks are ‘becoming less important’ as AI search rises. Here’s what the data actually shows:

92.3%Of top 100 ranking websites have at least one backlinkWytlabs, 2026

3.8xMore backlinks at position #1 vs positions 2–10Backlinko, 11.8M results

73.2%Of SEOs say backlinks are a primary AI Overview ranking factorEditorial.link, 2026

That last number is the 2026-specific insight worth paying attention to.

It’s not just Google rankings anymore. Backlinks — especially from authoritative editorial sources — now influence whether your content gets cited by AI tools like ChatGPT, Google’s AI Overviews, and Perplexity. We’ll cover this properly later in this guide.

For now, the core reasons backlinks still matter:

Reason 1: They Pass Authority (PageRank)

Every link on the web passes a portion of its page’s authority to the destination. This is called link equity (historically referred to as ‘PageRank’ or ‘link juice’). A link from a site with a Domain Rating (DR) of 80 passes significantly more authority than one from a DR 15 site. Every backlink you earn is a small — sometimes large — authority transfer to your domain.

Reason 2: They Signal Topical Relevance

Google doesn’t just count links. It reads them contextually. A link from a running blog to your marathon training guide tells Google something specific: this page is relevant to running, fitness, and endurance sports. The more relevant sites link to you, the stronger the topical relevance signal — which directly influences which keyword clusters you rank for.

Reason 3: They Drive Real Referral Traffic

This one gets overlooked. A backlink from a high-traffic site doesn’t just help your SEO — it sends real visitors to your site. Referral traffic from a well-placed link on a site with 500,000 monthly readers can drive thousands of clicks. These visitors arrive with existing context about who you are, which typically means higher engagement and lower bounce rates.

Reason 4: They Speed Up Indexing

Google discovers new pages by crawling links. When a new page on your site gets a backlink from an already-indexed, frequently-crawled domain, Google finds and indexes your page faster. For new sites and fresh content, this crawl discovery benefit is often more immediate than the ranking benefit.

Reason 5: They Build AI Visibility

In 2026, brand mentions from authoritative sources correlate 3x more strongly with AI citations than backlinks alone. (Source: Ahrefs, 2026.) When your content earns editorial backlinks from credible sites, you’re not just building Google authority — you’re building the kind of brand recognition that AI systems use to decide which sources to cite in AI-generated responses.

The 8 Types of Backlinks (And How Much Each One Is Worth)

Not all backlinks are created equal. In fact, the difference between your best backlink and your worst could be a factor of 1,000x in terms of SEO value.

Here’s the complete taxonomy:

Type	What It Is	SEO Value	How to Get It
Editorial backlink	A link a journalist, blogger, or author chose to include because your content genuinely adds value	★★★★★ Highest	Create genuinely valuable, citable content; digital PR
Guest post backlink	A link within an article you wrote for another site	★★★★☆ High (when from relevant, quality sites)	Guest posting outreach — see our full guide
Resource page backlink	A link from a curated ‘useful resources’ page in your niche	★★★★☆ High	Resource page outreach
Broken link replacement	Your content replaces a dead link on another site	★★★★☆ High	Broken link building — find dead links and offer yours
Directory backlink	A link from a business or niche directory	★★☆☆☆ Low–Medium (quality directories only)	Submit to Yelp, Clutch, industry-specific directories
Comment / forum backlink	A link in a blog comment, forum post, or community thread	★☆☆☆☆ Very Low (usually nofollow)	Generally not worth targeting; happens organically
Social media backlink	A link from a social media profile or post	★☆☆☆☆ Very Low (all nofollow)	Brand presence; drives traffic but not PageRank
Paid / sponsored backlink	A link acquired through payment, with rel=’sponsored’ tag	★☆☆☆☆ Zero (if properly tagged) or RISK (if untagged)	Not recommended — violates Google’s spam policies if untagged

The single most important insight from this table: one high-quality editorial backlink from an authoritative, relevant site is worth more than hundreds of directory links, comment links, and low-quality guest posts combined. Quality has always mattered. In 2026, it’s the only thing that matters.

Dofollow vs. Nofollow Backlinks: The Difference That Matters

Every backlink is either dofollow or nofollow. Understanding the difference is essential.

Dofollow Links

A dofollow link (the default) tells search engines to follow the link and pass authority from the linking page to the destination. This is the type of link that directly contributes to PageRank and search rankings.

Dofollow link HTML (no attribute needed — it’s the default):<a href=”https://linkbuildingjournal.co.uk”>Link Building Journal</a>

Nofollow Links

A nofollow link includes a rel=”nofollow” attribute that tells search engines not to pass authority. Wikipedia uses nofollow on all external links. So do most social media platforms, press releases, and paid content.

Nofollow link HTML:<a href=”https://linkbuildingjournal.co.uk” rel=”nofollow”>Link Building Journal</a>

What Makes a Backlink Valuable? The 6 Quality Factors

In 2026, Google evaluates backlink quality through at least six distinct signals. Understanding each one changes how you think about which links to pursue.

Quality Factor 1: Domain Authority of the Linking Site

A link from The New York Times is worth more than a link from a brand-new blog with zero readers. Tools like Ahrefs measure this as Domain Rating (DR) — a 0–100 scale. A link from a DR 80 site passes dramatically more authority than one from a DR 10 site. As a working rule: prioritise links from sites with DR 30+ and genuine organic traffic.

Quality Factor 2: Topical Relevance

A backlink from a website that covers the same topic as your page is worth significantly more than one from an unrelated site. A link to your link building guide from an SEO blog is far more powerful than the same link from a cooking website — even if the cooking site has higher authority. Google understands topical clustering. Links within your topic cluster reinforce it.

Quality Factor 3: Placement on the Page

In-content links — placed within the main body of an article — pass more authority than links in headers, footers, or sidebars. A sitewide footer link from a DR 60 site might actually pass less value than a single in-content link from a DR 40 article, because Google’s algorithms apply greater scrutiny to links that appear on every page of a domain.

Quality Factor 4: Anchor Text

The clickable text of the link tells Google something about the destination page. But there’s a balance to strike. Too many exact-match keyword anchors across your backlink profile is one of the fastest ways to trigger Google’s Penguin algorithm. A healthy anchor distribution blends branded anchors, partial match phrases, naked URLs, and natural language. For the full anchor text strategy, see our dedicated guide: The Complete Guide to Anchor Text for SEO.

Quality Factor 5: Link Freshness

Links from recently published, actively maintained pages carry more signal than links buried in content from 2015 that never gets updated. A link from a page that was just published and is already getting traffic is a stronger fresh signal than a dormant link from years ago.

Quality Factor 6: Uniqueness of the Referring Domain

Getting 50 links from a single domain is far less valuable than getting links from 50 different domains. Google weights referring domain diversity heavily. This is why the metric ‘Referring Domains’ in Ahrefs and Semrush is often a stronger authority predictor than raw backlink count.

What Makes a Backlink Harmful? (Toxic Links Explained)

Just as some backlinks help your rankings, some can hurt them — or at least be a waste of everyone’s time.

Here’s what to watch for:

Links from sites with no organic traffic and no real editorial content — these are the classic link farms
Links with excessive exact-match commercial anchor text from low-quality sources — the core Penguin trigger
Links from sites with topics completely unrelated to yours — a gambling site linking to a children’s education blog helps no one
Sitewide links — the same link appearing in the footer or sidebar of every single page of a domain
Links from domains Google has issued manual actions against
Sudden, coordinated spikes of new links from the same source — the signature of a negative SEO attack

The important nuance: most ‘bad’ links are simply ignored by Google, not weaponised against you. Google’s SpamBrain AI processes hundreds of algorithm updates per year and neutralises the majority of low-quality links automatically. The scenarios where bad links actually cause penalties are narrower than most SEO guides suggest. For a full walkthrough, see our backlink audit guide.

Backlinks and AI Search: The 2026 Dimension

Here’s the conversation that most ‘what are backlinks’ guides are not having yet:

In 2026, the value of a backlink extends beyond Google rankings into the emerging world of AI-powered search.

Google’s AI Overviews, ChatGPT, Perplexity, and other AI assistants are increasingly the first point of contact between users and information. These systems learn which sources to trust — and cite — based on signals that overlap significantly with traditional link authority.

73.2%Of SEOs believe backlinks drive AI Overview appearancesEditorial.link, 2026

3xBrand mentions correlate stronger with AI citations than backlinks aloneAhrefs, 2026

23xBetter conversion rate: AI search visitors vs traditional organic3way.social, 2026

What this means in practice:

Earning editorial backlinks from authoritative, brand-recognised publications builds the brand authority that AI systems weight when selecting citations
Unlinked brand mentions — someone writing your brand name without a hyperlink — now carry independent authority signals that AI tools recognise and weight
The quality threshold for backlinks that contribute to AI visibility is higher than for traditional SEO — low-quality links don’t help here at all
Building a strong backlink profile and building brand recognition are now the same strategic objective, not two separate activities

The Backlinko framing for 2026: ‘Link building in 2026 isn’t about chasing PageRank. It’s about shaping how your brand is recognised — by people and by machines. That’s the real game now. Not just Search Engine Optimisation. Search Everywhere Optimisation.’ (Source: Backlinko, 2026)

Backlinks vs. Internal Links: What’s the Difference?

Quick clarification that trips up a lot of people new to SEO:

Link Type	Definition	Who Controls It	Primary SEO Function
Backlink (external)	A link FROM another domain TO your site	Third-party site owners	Passes authority and topical relevance from other sites to yours
Internal link	A link from one page on YOUR site to another page on YOUR site	You (fully)	Distributes authority across your site; signals content hierarchy; aids crawlability
Outbound link	A link FROM your site TO another domain	You	Signals trust and relevance to destination; can help you earn reciprocal links

Both matter for SEO. Backlinks build your domain’s authority relative to the rest of the web. Internal links distribute that authority across your site and help Google understand your content structure. For the complete internal linking strategy, see our guide on Internal Linking Strategy for SEO.

How to Check Your Backlinks

You can’t manage what you can’t measure. Here are the main ways to see who’s linking to you:

1. Google Search Console (Free)

Navigate to Google Search Console → Links → Top Linking Sites. This shows you the referring domains Google has identified for your site. It’s authoritative data — it’s what Google actually sees. The limitation: no quality metrics like DR or traffic estimates.

2. Ahrefs (Most Comprehensive)

Enter your domain into Ahrefs Site Explorer and open the Backlinks tab. You’ll see every known referring domain, the DR of each, anchor text, and whether each link is followed. Ahrefs Webmaster Tools gives you this data for free for verified site owners.

3. Semrush (All-in-One Option)

The Semrush Backlink Analytics tool provides a full profile view including authority scores, toxicity indicators, and a competitor gap analysis feature. Useful if you’re already using Semrush for broader SEO work.

4. Moz Link Explorer (Budget Option)

The Moz Link Explorer free tier allows limited domain checks and shows Domain Authority (DA) and Spam Score alongside referring domain data. A good starting point if you’re not ready for a full Ahrefs or Semrush subscription.

For a complete step-by-step backlink audit using these tools, including how to identify and deal with problematic links, see our full guide: How to Do a Backlink Audit (Step-by-Step).

How to Get More Backlinks: The Strategies That Work in 2026

This guide focuses on what backlinks are. For the complete playbook on how to build them, read our dedicated guide: 15 Link Building Strategies That Actually Work in 2026. But here’s a quick overview of the most effective methods:

Strategy	How It Works	Difficulty	Time to First Link
Create linkable assets	Publish original research, comprehensive guides, or free tools that people naturally cite	Medium	Weeks to months
Guest posting	Write articles for other sites in your niche; earn a contextual backlink in return	Medium	1–4 weeks
Broken link building	Find dead links on other sites and offer your content as a replacement	Medium	1–2 weeks
Digital PR	Create newsworthy data or stories that earn editorial coverage from journalists	High	Weeks to months
Resource page outreach	Pitch your content for inclusion on curated resource pages in your niche	Low–Medium	1–3 weeks
Unlinked brand mention reclamation	Find sites that mention your brand without linking and ask them to add the link	Low	Days to 1 week
Competitor backlink replication	Use Ahrefs to find sites linking to competitors and pitch them your equivalent content	Medium	2–4 weeks

Frequently Asked Questions

Are backlinks still important in 2026?

Yes — they remain one of Google’s three most important ranking factors alongside content quality and user experience. The #1 Google result has 3.8x more backlinks than pages in positions 2–10. The difference in 2026 is that quality has become the only variable that matters — a small number of authoritative, relevant editorial backlinks consistently outperforms a large volume of low-quality links. Backlinks also now influence AI search visibility, adding a second dimension of value beyond traditional Google rankings.

How many backlinks do I need to rank on page 1?

There’s no universal answer — it depends entirely on the competitiveness of your target keyword. For low-competition long-tail keywords, a handful of quality backlinks may be enough. For competitive commercial terms, you may need dozens to hundreds of referring domains from authoritative sites. The most useful approach: use Ahrefs or Semrush to analyse the backlink profiles of the pages currently ranking in positions 1–5 for your target keyword. That tells you the benchmark you need to reach or exceed.

Can I buy backlinks?

Buying links violates Google’s link spam policies. Paid links that are not tagged with rel=”sponsored” can result in algorithmic devaluation of those links or, in severe cases, a manual penalty. The risk-to-reward calculation is unfavourable: you pay for links that Google is increasingly good at identifying and ignoring, while risking your entire domain’s authority. Focus on earning links through white-hat tactics instead.

What is a ‘natural’ backlink profile?

A natural backlink profile is one that looks like it was built through genuine editorial decisions rather than deliberate manipulation. It includes a mix of anchor text types (branded, partial match, generic, naked URL), links from a range of domain authority levels, a diversity of referring domains rather than many links from a few sources, a gradual accumulation rate over time rather than sudden spikes, and links from topically relevant pages. No real site earns 100% exact-match anchor links from high-DR sites overnight — and Google’s algorithms are calibrated to know this.

Social media links are almost universally nofollow, which means they don’t pass PageRank or directly contribute to your search rankings. However, social media links do drive referral traffic, can amplify content visibility (increasing the probability of earning organic editorial backlinks), and contribute to the brand recognition signals that AI search systems weight. They’re a valuable part of a content distribution strategy — just not a direct substitute for editorial backlinks.

What’s the difference between a backlink and a referring domain?

A backlink is a single link. A referring domain is the entire website that link comes from. If the same site links to you 10 times, you have 10 backlinks but only 1 referring domain. Referring domain count is generally a more useful metric than raw backlink count, because Google values link diversity — 10 links from 10 different quality sites is more powerful than 10 links from the same site.

The Bottom Line on Backlinks

Here’s what you need to remember:

A backlink is a link from another website to yours — one of Google’s most important ranking signals since 1998
Quality completely dominates quantity — one editorial link from an authoritative, relevant site is worth more than hundreds of low-quality links
The six factors that determine a backlink’s value: domain authority, topical relevance, page placement, anchor text, link freshness, and referring domain uniqueness
In 2026, backlinks now serve double duty: they build Google rankings AND influence AI search citations
The best backlinks are earned, not manufactured — through great content, smart outreach, and genuine relationships

Ready to start building backlinks? Start with our complete guide to link building strategies. Want to audit what you already have? Use our step-by-step backlink audit guide. Need the right tools? See our full review of the best link building tools in 2026.

Link Type	Attribute	Passes PageRank?	SEO Value
Standard editorial link	None (default)	Yes	Full link equity
Nofollow	rel=”nofollow”	No (technically)	Brand visibility, referral traffic
Sponsored	rel=”sponsored”	No	Compliance — required for paid links
UGC (user generated)	rel=”ugc”	No	Low — used for comments, forum posts