A backlink is a hyperlink on one website that points to a page on another website. When Site A links to Site B, Site B has received a backlink from Site A. Also called inbound links, incoming links, or external links (from the receiving site's perspective).
Simple Definition#
Think of a backlink as a citation or reference. When someone links to your website, they're essentially saying "this page has something worth looking at." Search engines interpret backlinks as votes of confidence.
Example: If a news article about gardening links to your plant care guide, you've earned a backlink from that news site.
Why Backlinks Matter#
Search Engine Ranking Factor#
Backlinks have been a core ranking factor since Google's founding. The original PageRank algorithm was built on the idea that pages with more quality links deserve higher rankings.
How search engines use backlinks:
- Measure authority and trust
- Understand topic relationships
- Discover new content
- Validate content quality
Referral Traffic#
Beyond SEO, backlinks drive direct visitors. When someone clicks a link to your site, that's referral traffic—often high-quality since it comes with context.
Discovery and Indexing#
Search engine crawlers follow links to discover new pages. Backlinks help ensure your content gets found and indexed.
Backlink Anatomy#
Every backlink has key components:
Source Page#
The page containing the link (where the link comes from).
Target Page#
The page being linked to (where the link points).
Anchor Text#
The clickable text of the link. Provides context about the target page.
Link Attributes#
HTML attributes that modify link behaviour:
rel="nofollow"- Suggests not passing ranking valuerel="sponsored"- Marks paid linksrel="ugc"- Marks user-generated content
Link Context#
The surrounding content and the linking page's topic affect how search engines interpret the link's relevance.
Types of Backlinks#
By Link Attribute#
Do-follow links: Standard links that pass ranking signals. Most valuable for SEO.
No-follow links: Links with rel="nofollow" attribute. Originally didn't pass value; Google now treats as a "hint."
Sponsored links: Marked as paid/advertisement with rel="sponsored".
UGC links: Links in user-generated content marked with rel="ugc".
By Acquisition Method#
Natural/Editorial links: Given organically because someone found your content valuable.
Outreach links: Earned through direct contact—guest posts, resource requests, etc.
Self-created links: Placed by you in forums, comments, directories. Generally lowest value.
By Placement#
Contextual links: Within body content, surrounded by relevant text. Most valuable.
Navigation links: In menus or site navigation.
Footer links: In page footers. Often site-wide.
Sidebar links: In page sidebars or widgets.
Comment links: In blog comments. Usually nofollow.
What Makes a Good Backlink?#
Quality Indicators#
Relevance: Link comes from a topically related site or page.
Authority: Linking site has strong domain authority and trust.
Placement: Link is contextual, within main content.
Editorial: Link was given naturally, not paid for or exchanged.
Traffic: Linking site has real visitors, not just metrics.
Warning Signs#
Irrelevance: Link from completely unrelated site.
Spam signals: Linking site is low-quality or spammy.
Manipulation: Link was clearly paid for or part of a scheme.
Over-optimised anchor text: Exact-match anchor text at scale.
Backlink vs Related Terms#
Backlink vs External Link#
Same link, different perspective:
- Backlink: Viewed from the receiving site's perspective
- External link: Viewed from the linking site's perspective
Backlink vs Internal Link#
Different link types:
- Backlink: From another domain to yours
- Internal link: From one page on your domain to another
Backlink vs Referring Domain#
Different metrics:
- Backlink: An individual link
- Referring domain: A unique domain that links to you (may have multiple backlinks)
How to Get Backlinks#
Content-Driven Methods#
- Create comprehensive, valuable content
- Publish original research with data
- Build useful tools or resources
- Develop visual content (infographics, charts)
Outreach Methods#
- Guest posting on relevant sites
- Resource page link building
- Broken link replacement
- Digital PR and media coverage
Relationship Methods#
- Build industry connections
- Participate in communities
- Collaborate with complementary businesses
Full guide: How to Start Link Building →
Measuring Backlinks#
Key Metrics#
Total backlinks: Raw count of all links pointing to your site.
Referring domains: Unique domains linking to you (often more meaningful than total links).
Do-follow ratio: Percentage of links passing ranking value.
Anchor text distribution: Mix of anchor text types.
Domain authority of sources: Quality level of linking sites.
Tools for Analysis#
- Ahrefs
- Semrush
- Moz Link Explorer
- Google Search Console (limited but free)
- Majestic (explore alternatives to Majestic if you need different features)
On a budget? Check out our roundup of free tools for checking backlinks to get started without a paid subscription.
Common Questions#
How many backlinks do I need?#
There's no universal number. Focus on quality over quantity. The "right" number depends on your competitive landscape—analyse competitors ranking for your target keywords.
Do all backlinks help?#
No. Low-quality, spammy, or irrelevant backlinks can potentially harm your rankings. A few quality backlinks often beat many poor ones.
How long until backlinks impact rankings?#
Varies significantly—days to months. New links need to be discovered and processed. Impact depends on the link's quality and your site's existing authority.
Should I disavow bad backlinks?#
Only if you have clear evidence of spammy links and potential penalty risk. Most sites don't need to use disavow.
Summary#
A backlink is a link from another website to yours. Backlinks:
- Act as votes of confidence
- Influence search rankings
- Drive referral traffic
- Help with content discovery
Focus on earning quality backlinks from relevant, authoritative sources through valuable content and legitimate outreach.
Free Tools#
- Free Backlink Checker - Check any website's backlinks instantly
- Backlink Audit Checklist - Step-by-step audit guide