Link Building

What Are Backlinks in SEO? Everything You Need to Know

Mateusz Makosiewicz
Marketing researcher and educator at Ahrefs. Mateusz has over 10 years of experience in marketing gained in agencies, SaaS and hardware businesses. When not writing, he's composing music or enjoying long walks.
    Backlinks (aka inbound links, incoming links) are links from a page on one website to another. Search engines like Google use backlinks as votes of confidence in ranking pages.
    What are backlinks

    Backlinks are important for SEO (Search Engine Optimization) because of two main reasons: 

    1. Search engine rankings – Generally speaking, the more backlinks your web pages have, the more likely they are to rank for relevant search queries (we confirmed this in a study). 
    2. Discoverability – Search engines revisit popular pages more often than unpopular ones. And they may discover your content faster if you get backlinks from popular pages.

    There are two ways to check a website’s links.

    The first method only works for sites that you own. Use the second one to check backlinks to another website or web page.

    Checking backlinks to your website 

    A basic tool for checking your website backlinks is the free Google Search Console. 

    Once signed in, click “Links” on the sidebar. The number below “External links” shows the total number of unique backlinks to the website.

    How to check backlinks in Google Search Console

    Google Search Console shows limited data in the app (top 1,000 links) and won’t show you some useful SEO metrics you could use to analyze your backlinks. To get more data for free, you can use Ahrefs Webmaster Tools

    Once you set up a project, click on Backlinks in the dashboard. 

    Backlinks summary in Ahrefs' dashboard

    This will take you to the Backlinks report in the Site Explorer tool. This report will show all your backlinks and relevant backlink data. 

    See your backlinks in Ahrefs' Site Explorer

    Checking backlinks to another website 

    You can start with a tool like Ahrefs’ free backlink checker

    Just enter a domain or URL, and hit “Check backlinks.”

    Ahrefs' free backlink checker

    You’ll see the total number of backlinks and referring domains (links from unique websites), plus the top 100 backlinks.

    Backlink profile in Ahrefs' free backlink checker

    To see a full list of backlinks to any page or website, use Ahrefs’ Site Explorer

    Not all backlinks are created equal. Here are some of the many attributes that contribute to a backlink’s quality and utility. You can use them to analyze your backlinks and link building opportunities to find high-quality backlinks: 

    • Authority
    • Relevance
    • Anchor text 
    • Follow (aka dofollow links) vs. nofollow links
    • Placement 
    • Destination 
    What makes a good link

    Let’s look at them in more detail. 


    Backlinks from strong web pages usually transfer more “authority” than weak ones.

    Pages that have backlinks cast a stronger vote

    We’ve studied page-level authority a few times, and we’ve found a clear relationship between it and organic search engine traffic.

    UR Rating vs. search traffic
    URL Rating (UR) is Ahrefs’ page-level authority metric. It’s scored on a scale from 0 to 100.

    That said, backlinks from high-authority websites don’t always transfer more authority. 

    The more links there are on the page that links to you, the less authority will be transferred to you because it’s shared between all of those pages (due to the PageRank algorithm). 

    You can gauge a backlink’s authority by using the UR metric in the Backlinks report in Ahrefs’ Site Explorer. (You can also find it in other Ahrefs tools where relevant.) The higher the UR, the better. 

    UR metric in Ahrefs' Backlinks report


    Links from websites on the same topic as yours are deemed to bring more value. Google states this in its “How Search Works” guide:

    If other prominent websites on the subject link to the page, that’s a good sign that the information is of high quality.

    Say a plumber has backlinks from two pages: one about cats, and one about installing boilers. Relevance in this context means that chances are the latter link is most valuable.

    Backlinks from relevant pages are more valuable

    Anchor text 

    Anchor text refers to the clickable words that form a backlink.

    Example of a link anchor

    Google says that anchor text influences rankings in its original patent.

    Google employs a number of techniques to improve search quality, including page rank, anchor text, and proximity information.

    You can see the anchor text of any backlink using a backlink analysis tool like Site Explorer.

    Checking the anchor text of backlinks in Backlinks report, via Ahrefs' Site Explorer

    You can also filter for certain words in the anchor text. 

    "Anchor text" filter in Backlinks report

    Follow vs. nofollow links

    Nofollow backlink is a link attribute that instructs Google not to follow the link and serves as a hint not to pass authority (as of 2019).

    Anatomy of a nofollow link

    A followed link is a link that doesn’t have that attribute nor the “sponsored” or “UGC” attributes. 

    Because nofollow backlinks usually don’t influence rankings, it’s best to prioritize getting followed links. 

    However, since “nofollow” is only a hint now, pursuing a nofollow link from a relevant high-authority page may still be a good idea.

    You can find these types of backlinks using filters in Site Explorer’s Backlinks report. 

    Filtering backlinks by rel attributes in Ahrefs


    Because people are more likely to click prominently placed links, some links on web pages likely pass more authority than others.

    Prominently placed links may transfer more authority

    Bill Slawski talks about this in his analysis of Google’s updated “reasonable surfer” patent:

    If a link is in the main content area of a page, uses a font and color that might make it stand out, and uses text that may make it something likely that someone might click upon it, then it could pass along a fair amount of PageRank. On the other hand, if it combines features that make it less likely to be clicked upon, such as being in the footer of a page, in the same color text as the rest of the text on that page, and the same font type, and uses anchor text that doesn’t interest people, it may not pass along a lot of PageRank.

    Consider this when pursuing links. If a website links to you along with 50 other sites through the sidebar or the footer, then put your energy into other opportunities.

    Something that can help you find backlinks placed in content (as opposed to less prominently placed links) is the “Backlink type” filter in Site Explorer’s Backlinks report. 

    Filtering by backlink type in Ahrefs


    Because Google ranks pages and not entire websites, it’s best to build links pointing directly to the page that you want to rank. 

    However, getting links to some page types is harder. For example, getting links to commercial pages is often difficult because people prefer linking to informative content. 

    To address this, you can use internal links to pass authority from pages that get a lot of links to your important but “boring” pages. 

    Use internal links to transfer authority between your pages

    Generally, there are four ways to build backlinks to your site: 

    Four ways to get backlinks

    Adding backlinks 

    Some websites allow you to add a link either by manually submitting it or requesting to submit it. It’s easy to get a link this way, but it’s not always worth it. They can be low in value in the eyes of Google or even deemed spammy if you overdo it. 

    One of the most common (and legit) tactics here is to add your website to relevant local directories. They can help you rank for queries with local intent and get your business discovered by customers too. 

    Asking for backlinks 

    This is when you reach out to other site owners, editors, or webmasters and ask them to link to your page. For this to work, you need to have a clear value proposition. That’s where link building tactics come in.

    Here are a few tried and tested ones:

    • Guest blogging – Offer to write a one-off blog post for another website.
    • Broken link building – Find relevant dead links on other sites, then reach out and suggest your working link as the replacement. (You can use our broken link checker to do this.)
    • The Skyscraper Technique – Find relevant content with lots of links, make something better, then ask those linking to the original to link to you instead. Often used to pursue competitors’ backlinks.
    • Unlinked mentions Find unlinked mentions of your brand, then ask the author to make the mention clickable.

    Learn more about these tactics and others in the video and posts below.

    Buying backlinks

    Every now and then, you’ll come across an offer to buy links—don’t take it.

    Buying backlinks is extremely risky. Google is strongly against that, and you can get your site penalized.

    This is not to be confused with paid link building services. Good link building agencies use legit, white-hat tactics that have nothing to do with spam or buying links for that matter. 

    Earning backlinks 

    This is when people discover your content via Google (and other search engines), social media, or word of mouth and choose to link to your page. In other words, earned backlinks are organic.

    You can improve your chances of earning more backlinks by creating truly useful content that people should want to link to. 

    You should definitely promote your content too. The more people you reach, the more links you can get. 

    Basically, when pursuing backlinks, avoid anything that looks low-quality, spammy, or like an obvious link scheme (links in exchange for something).

    Bad links will be a waste of time because search engine algorithms are quite sophisticated. In the best-case scenario, they won’t have any impact on your rankings. At worst, they may make your pages rank lower on Google or even not appear at all

    Google advising that sites violating its policies will rank lower or not appear at all in results

    Here are some types of bad links you should definitely avoid:

    • PBNs – Multiple sites linking together in order to manipulate search engines.
    • Paid links – Exchanging money, goods, or services in return for links for ranking purposes.
    • Link exchanges – Linking to a site in exchange for that site also linking to yours.
    • Automated links – Use of automated software or services to generate large volumes of links to a site.
    • Forum and comment spam links – Adding spam links in forums as part of signatures.

    Final thoughts

    Backlinks are crucial for ranking on Google, especially for competitive queries. But the easier it is to get a link, the less valuable it’ll be.

    Looking to get started with link building? Read our beginner-friendly guide or watch our link building tutorials on YouTube

    Got questions? Let me know on Twitter or Mastodon

    Article Performance
    Data from Ahrefs
    • 10.47K
      Organic traffic
    • 806
      Linking websites

    The number of websites linking to this post.

    This post's estimated monthly organic search traffic.