Backlink Checker: check your link profile for free

What is a backlink?

A backlink is a link to a website from another domain. The concept became a ranking signal with the PageRank algorithm that Google's founders published in 1998. PageRank calculates a page's value from the number and authority of the pages linking to it. Google has expanded its signal set since then, but the link graph is still part of the evaluation, and every major SEO tool tries to model that graph in its own index.

Links differ in how much authority they pass. Google announced the rel="nofollow" attribute in January 2005; rel="sponsored" and rel="ugc" followed in September 2019, and nofollow changed from a strict rule into a hint for ranking. In March 2020 the hint approach was extended to crawling and indexing. A profile's strength is measured with metrics such as total backlinks, referring domains (the number of unique linking domains) and spam score; the backlink checker on this page shows 6 metric cards and the anchor list in a single query.

How do you check backlinks?

Checking backlinks on this page takes three steps: enter the domain, press Analyze, read the report. Guests get 3 queries per day and free members get 10 per day; results for the same domain are cached for 24 hours. Three details work behind the scenes:

1. The tool cleans up your input: https, www and the page path are stripped, and the query runs in site.com format.
2. The report counts only live links, meaning links that are still published; subdomains are included.
3. Below the metric cards, 8 anchor rows are listed, sorted by number of backlinks.

The cards answer three separate questions: the first three measure volume and source base, spam score and dofollow ratio measure risk, and broken backlinks measure authority you are losing. The table summarizes how to read each card:

Metric	What does it count?	How to read it
Total backlinks	All live links pointing to the site	Shows volume, not quality
Referring domain	Unique domains linking to the site	The main indicator of authority
Referring IP	Distinct servers the links come from	A low value may point to a single network
Spam score	Risk score from 0 to 100	A low value means a healthy profile
Dofollow ratio	Share of links that pass authority	A natural profile has a mix
Broken backlinks	Links pointing to pages that return 404	Authority you can win back

Why do referring domains matter more than total links?

Referring domains are a more reliable measure of authority than total backlinks, because each unique domain counts as an independent vote of trust. A link placed in one site's footer repeats across thousands of pages and inflates the total on its own; the report counts it as one referring domain. Fifty links from fifty different sites are a stronger foundation than five thousand links from a single site.

The ratio is telling too. If total backlinks are hundreds of times the number of referring domains, the profile usually leans on sitewide links; the number looks big, but the source base is narrow. That is why the goal of link building is to win new, relevant domains, not to multiply links from the same source.

How should you read the spam score?

The tool reports the spam score on a 0-100 scale and colors it in three bands: 0-15 low, 16-45 medium, 46 and above high risk. The score is an estimate calculated from spam signals in the linking sources; it is not Google data and does not by itself mean a penalty.

Three source types usually push the score up: irrelevant directories, auto-generated comment links and link networks that point to each other. With a high score, the first step is reviewing sources, not a mass cleanup: the report does not show which link was added recently, but a low referring IP count together with repeated anchors reveals a problem network. A broad disavow made before you know which sites drive the score can also remove links that help you.

Why is anchor distribution a sign of over-optimization?

An anchor is the clickable text of a link, and its distribution reveals whether a profile grew naturally or was engineered. In natural profiles, brand names, naked URLs and generic phrases such as "click here" are the majority. Exact match anchors built on money keywords stay in the minority. If a commercial phrase is both at the top of the list and well ahead of the brand name, the pattern usually points to templated link buying.

Google has targeted this pattern for a long time: the Penguin algorithm, aimed at over-optimized anchors and artificial link schemes, launched in April 2012. Penguin 4.0 in September 2016 moved the filter into the core algorithm and made it real-time; since then Google prefers to devalue spam links rather than penalize the whole site. The penalty risk is lower, but a devalued link is wasted budget: a paid anchor produces no signal at all.

Why do Ahrefs, Semrush and Moz show different results?

Every tool runs its own crawler and builds its own link index; Ahrefs, Semrush, Moz and Majestic crawl the same site with different coverage, so they report different totals. The gap is an index difference, not a data error. Four variables separate the numbers: crawl budget, how live and deleted links are defined, subdomain coverage and update frequency. There is no shared standard for risk either; Moz uses its own Spam Score model, and the score on this page is calculated by the index that feeds it.

Google does not open its own link graph to any third-party tool. Search Console offers a slice of Google's records in its Links report, but it has no evaluation layer such as a spam score or anchor breakdown. The practical takeaway: track the trend rather than absolute numbers, and always compare within the same tool, because measuring with Ahrefs one month and Semrush the next creates artificial drops or gains.

How do you analyze competitor backlinks?

Competitor backlink analysis means checking the domains that outrank you for a target keyword and comparing them with your own report. It is quick to do: check two or three competitors ranking on page one in this tool, one by one, and note their referring domains, spam score and top three anchors side by side. The referring domain gap shows the authority deficit you need to close, and the anchor list shows which keywords the competitor is collecting links for.

How you use the comparison depends on your role. For an agency, this table is the data behind a proposal: if the client's site sits below the competitor range, the first budget item is the link base. For a site owner the reading is simpler: a competitor with a low spam score and many referring domains is the right profile to follow. A high-scoring competitor ranking ahead does not prove that the tactic works, because rankings depend on content and technical health as well as links.

When should you disavow harmful links?

To disavow is to ask Google, through a list uploaded in Search Console, to ignore specific links. In its documentation on disavowing links, Google recommends the tool only when two conditions are met together: the profile has a large number of spammy or artificial links, and those links have caused, or are likely to cause, a manual action. The same document warns that misusing the tool can hurt your site's performance.

In practice the order is: first check Search Console messages for a manual action; if there is none, monitoring is usually enough, because Google ignores most spam links without counting them. If there is one, list the risky sources and ask the sites you can reach to remove the links. Put the rest in a plain text (.txt) file: one URL per line, or the domain:site.com pattern for a whole domain. The process is the same if you suspect negative SEO; without a penalty, such an attack usually has no effect.

What does backlink data change in practice?

The report clarifies four decision points. For a site owner learning SEO, the first measure is the referring domain base: if it is below the competitor range, the priority is winning new, relevant sources. For agency staff, the main output is the competitor comparison; a table of referring domains and anchors for three competitors becomes the data behind the proposal and the plan.

On the risk side, the decision depends on manual actions: if the spam score reaches the 46+ band, it needs checking; if there is no penalty, monitoring is enough; if there is one, disavow comes into play. When choosing a tool, consistency is what counts: differences in numbers are normal, so track growth in one tool at monthly intervals. These four readings turn the same report into different decisions depending on who is reading it.