How to do a backlink gap analysis (and why the export is not a target list)

A backlink gap is the set of domains that link to your competitors and not to you. A tool will show you that set, but it will not tell you which of those links you can actually get, or whether they are the reason the competitor ranks.

Below we show you how to run a backlink gap analysis in Semrush, Ahrefs and a free tool, how we sort the export into replicable and non-replicable links on every managed campaign we run, and how to turn the replicable set into an ordered target list.

What a backlink gap analysis is

A backlink gap analysis is a set difference between backlink profiles. You compare the referring domains of several competitors against your own site and keep the domains that link to them but not to you: theirs but not yours.

The analysis is worth doing because those domains have already shown they link out on your topic. A site that links to three of your competitors has made that editorial decision three times, which makes it a warmer prospect than any cold list of sites in your niche.

Links are the reason this matters. Followed links from relevant, indexed, read publications are one of the strongest ranking levers an agency can move once a page is ready. Google's own How Search Works documentation says that one factor used to determine quality is whether other prominent websites link or refer to the content, and treats that as generally a good sign the information is trustworthy. Google's ranking systems guide still lists link analysis systems and PageRank among its core ranking systems.

If you want to read a rival's link profile in full before you run the comparison, our guide to competitor backlink analysis covers that step.

What a gap does and does not tell you

A backlink gap tells you who links to your competitors and not to you. It does not tell you that those links caused the competitor's rankings, and it does not tell you which of the domains are worth pursuing.

The first limit is causation. Patrick Stox put it carefully on the Ahrefs blog on 15 December 2022:

If you look at well-ranking competitors and they have a lot of the same links, those links may be the ones helping them to rank.
Patrick Stox, Ahrefs blog, 15 December 2022

"May be" is doing the work in that sentence. An overlap between competitor links and competitor rankings is a correlation. The gap export on its own cannot prove the links caused the rankings, so treat every domain on the list as a lead to check, not a result to copy.

The second limit is coverage. In the same Ahrefs piece, Stox warns:

A lot of these links may be unique to a particular competitor, and you may miss them when looking at the overlap of competitor links.
Patrick Stox, Ahrefs blog

The links that make one competitor stand out are often unique assets: a tool, a study, a quote that people reference. An intersect report never shows those, because they appear for one domain only. The gap list is a floor for your research, not a ceiling.

The third limit is metrics. Domain Rating is Ahrefs' 0 to 100 score for the relative strength of a website's backlink profile, and Ahrefs' Tim Soulo wrote on 4 May 2022 that DR does not account for backlink spam: large amounts of low-quality links may actually increase a site's DR, not decrease it. Soulo also notes that a relevant low-DR link will still help a page rank better. Moz says the same about its own Domain Authority score: in guidance dated 18 March 2025, Moz states that DA is a predictive metric and is not used by Google to determine search engine rankings. Majestic's Trust Flow and Citation Flow are 0 to 100 scores of the same kind, and Majestic says its Flow Metric scores do not directly influence search engines.

So a DR or DA floor is a sorting aid for a long list, not a quality filter. We do not set Domain Rating to a minimum of 50 and ignore everything below it, because spam can inflate DR and relevance often lives on small, read sites.

How to run it

You can run a backlink gap analysis in Semrush, Ahrefs or one of several free tools. The paid tools compare more competitors and show more data per domain.

In Semrush (Backlink Gap)

Semrush's Backlink Gap tool, part of the Semrush SEO toolkit, compares the backlink profiles of up to five competing websites at once, and each entry can be a root domain, a subdomain or an individual URL (checked 12 September 2026). The Semrush Backlink Gap documentation walks through the setup.

Enter your own domain in one of the five fields and the report isolates the domains that link to the competitors but not to you. The filter you will work from is Best: domains that link to every competitor you entered and not to your site. Weak, Strong, Shared and Unique filters cover the other combinations.

The results table shows an Authority Score, Monthly Visits and a Matches count for each domain. Matches is the overlap count: how many of your entered competitors that domain links to.

Semrush limits Backlink Gap by plan. Pro accounts get 3,000 requests a day and 10,000 results per report, Guru gets 5,000 requests and 30,000 results, and Business gets 10,000 requests and 50,000 results. Semrush lists Backlink Gap limits for the Pro, Guru and Business SEO plans only; the 7-day trial is long enough to run the analysis for one site and export the list.

In Ahrefs (Link Intersect)

Ahrefs runs its gap analysis through Link Intersect, which now sits under Competitive Analysis in the top navbar (checked 12 September 2026). According to the Ahrefs Link Intersect help page, the tool is available on all subscription plans and lets you enter up to 10 competitors to compare against.

Add your competitors, leave your own site out of the list, and set the mode. Referring domains mode gives you the domain-level gap, which is the working view for building a target list. Referring pages mode shows the exact pages that link out, which helps when you want to see the context of a link before you pursue one. The Show link opportunities button runs the report.

Ahrefs includes DR and traffic filters on the Link Intersect report. Treat them as a way to shorten a long list, not as a quality gate: Ahrefs' own workflow guide of 30 January 2025 suggests trying a DR minimum of 50, or a traffic minimum of 1,000, only when the list is still long, and adjusting the values up or down.

With a free tool

Five free or trial options will run a backlink gap without a paid subscription. The limits below are checked 12 September 2026.

Keywords Everywhere runs a free Backlink Gap Analyzer that works on a whole website or a single webpage. The free tier compares up to 2 competitors and allows 500 backlinks a day shared across the Keywords Everywhere backlink tools. Keywords Everywhere is open about the trade-off: its coverage is a sample, not a census, and the tool does not yet split followed and nofollowed links.

linkgap.io offers a free Backlink Gap Analyzer with no credit card required, and says it analyses 500+ backlinks per site. SE Ranking's Backlink Gap Analyzer compares up to 5 competitors with up to 10,000 backlinks per domain or URL; SE Ranking's public backlink checker is free as a snapshot, with the full tool on a 14-day trial and then any paid plan.

Moz's Link Explorer still includes a Link Intersect view that compares up to five backlink profiles against your own; a free Moz Community account gives 10 queries a month. SEO PowerSuite's desktop SEO SpyGlass examines backlink gaps in bulk, and its free version covers 1,100 backlinks per site across 2 competitors.

The limits side by side, checked 12 September 2026:

What none of these tools do, paid or free, is tell you which domains on the export you can actually get a link from. Deciding that is a human sort, and that sort is the next step.

Replicable or not: how we sort the list

Every domain on a backlink gap export is either replicable or non-replicable, and we make that call by opening the site, never by reading a metric off the export.

Every managed campaign we run starts with this analysis, and the first lesson is always the same: a tool export is not a target list. We open every competitor referring domain and sort it before anyone pitches a placement or we place a Curated Link or Guest Post.

Replicable:

• An editorial placement on a real, indexed site with readers: the kind of page that becomes a Curated Link or Guest Post target.

Non-replicable:

• Brand PR coverage
• Partner and supplier links
• Directories
• Syndication
• Spam and paid-network footprints

The non-replicable set still has a use. It shows what the competitor's brand earns on its own: the coverage, relationships and listings that a placement cannot copy. Knowing that stops you pitching a partner page that was never going to link to you.

Relevance is the thread through the whole sort. Kevin Indig wrote in the Growth Memo on 20 May 2025:

Backlinks provide another confidence layer for Google that your content is good and relevant for a specific topic.
Kevin Indig, Growth Memo, 20 May 2025

A link only works as that confidence layer when the page carrying it is on your topic and read by people.

Turning the replicable set into a target list

The replicable set becomes a target list when you order it, and the order we use is relevance and readership, not Domain Rating.

Charles Floate posted the working rule on X on 5 February 2026:

It's not about having "more links." It's about having the RIGHT links that match the trusted linkgraph of your niche. Run Ahrefs link intersect on your top 15 competitors. The overlap from at least 5/15 will tell you exactly the links you need to get!
Charles Floate, X, 5 February 2026

The first sort is the overlap count: how many of your compared competitors a domain links to. A domain linking to four of five competitors is a stronger consensus target than a domain linking to one. The second sort is relevance and readership: does the site publish on your topic, and does the page have real visitors. The Zyppy 2026 expert survey, run by Cyrus and Dawn Shepard and published on 9 September 2026, found that respondents rated links from trusted, relevant sites among the most important ranking factors, and many stressed links from pages with real visitors.

Before any placement from the list, we run the cross-checks in our link building quality assurance standard: a traffic floor, a DR/DA cross-check rather than a DR gate, no PBNs or networks, in-body links only, human sign-off and a post-publication check. DR appears in that list as a sanity check, not as the sort key.

If the next question is how many of these targets a page needs before it moves, that depends on the search results you are chasing. We break the maths down in our guide to how many backlinks a page needs to rank.

A worked example: the sheet we use

The sheet we fill in on every gap run has seven columns, one row per competitor referring domain, and no row is pitched until every column is filled.

The column headers:

Competitor is the competing site the domain links to. Referring domain is the domain that links to the competitor and not to you. Overlap count is how many of your compared competitors the domain links to. Replicable is our call after opening the site, and Why is the reason for that call, such as an in-body editorial mention or a footer partner logo. Target URL is the page on your site the link would point to, and Product is Curated Link or Guest Post.

A row moves on its evidence. A domain that links to three of five competitors from an in-body editorial mention on an indexed page with traffic becomes a Curated Link target. A Curated Link costs $60 to $210 depending on the referring domains of the host, delivered in 14 to 21 days, and a Guest Post starts at $75, or $130 on a DA30+ site (checked 12 September 2026). A domain that links to all five competitors from a footer partner logo is non-replicable: we note it, and nobody pitches it.

Reporting the gap on a managed campaign

On a managed campaign, the gap list becomes the baseline we report against every month.

Every managed campaign includes a full backlink audit, keyword research, competitor analysis and monthly white-label reporting, so the gap analysis sits inside a wider piece of work rather than running as a one-off. Our managed link building service is built this way: a dedicated account manager runs the plan, the plan sets the target URLs and the anchor-text strategy, and the gap list feeds it. Managed campaigns start from $250 a month, and a first order across any of our services is refundable up to $550 (checked 12 September 2026).

The monthly report tracks new and lost placements against the gap list, with the target URL and the live link for each placement. Every delivered link carries 12-month replacement cover, so a link lost inside that window is replaced rather than written off. What the report does not do is present Domain Authority or Domain Rating as ranking scores: Moz and Ahrefs both describe those as their own predictive metrics, not Google inputs.

The gap list also sits next to the link audit of your existing profile, and we repeat the analysis when the competitor set changes: a new entrant outranks the page, or a rival rebrands. We do not rerun it on a fixed calendar, because a gap list only goes stale when the competitors do.

Frequently asked questions

What is a backlink gap analysis?

A backlink gap analysis compares the referring domains of competing websites against your own and keeps the domains that link to the competitors and not to you. The output is a set of proven linkers on your topic, which then needs sorting into replicable and non-replicable before it becomes a target list.

Does a backlink gap mean those links made the competitor rank?

No. Patrick Stox of Ahrefs puts it carefully: the shared links may be the ones helping well-ranking competitors to rank. A backlink gap analysis shows a correlation between shared links and rankings, and correlation is not proof that the links caused the rankings.

Should I filter by Domain Rating 50?

No. Domain Rating is a sorting aid for shortening a long list, not a quality filter. Ahrefs' Tim Soulo notes that DR does not account for backlink spam and that large amounts of low-quality links can raise a site's DR, so a DR 50 floor can keep inflated domains in and relevant small sites out.

What is the best free backlink gap tool?

Keywords Everywhere's free Backlink Gap Analyzer compares up to 2 competitors with 500 backlinks a day, and linkgap.io analyses 500+ backlinks per site with no credit card (checked 12 September 2026). Both trade coverage for cost: Keywords Everywhere notes that its coverage is a sample, not a census.

How many competitors should I compare in a backlink gap?

Semrush's Backlink Gap takes up to five competitors, Ahrefs' Link Intersect takes up to ten, and Charles Floate suggests running the intersect on your top fifteen. The useful number is whatever it takes to see real overlap: enough competitors that a domain linking to several of them means something.

How do I report backlink progress to a client?

Report new and lost placements against the original gap list each month, with the target URL and the live link, and note any links replaced under the replacement cover. Avoid reporting Domain Authority or Domain Rating as Google ranking scores, because Moz and Ahrefs both describe them as third-party predictive metrics.

What is the difference between a backlink gap and a backlink profile?

A backlink profile is the full set of links pointing to one site: every referring domain, anchor text and target page. A backlink gap is a comparison between profiles: the domains that link to your competitors and not to you.