What Is a Backlink Gap Analysis?
A backlink gap analysis compares the websites that link to you with the websites that link to your competitors, and lists the sources they have that you don't. The result is a list of candidates to research, not a list of guaranteed opportunities.
The comparison is usually done by referring domain rather than by individual link. Ten links from one site to a competitor count as one referring domain. The comparison checks whether that domain appears in your supplied list, not whether it has ever linked to you. Once you know which domains are missing, you can look at the exact pages behind them and work out how each competitor earned the link.
How Do You Use This Free Tool?
Import your own referring-domain list, add two to five competitor lists, run the comparison and export the missing domains as a CSV.
- Add your site. Paste domains or URLs, one per line, or upload a CSV export. If the file has several columns, pick the one that holds the referring domain or source URL.
- Add two to five competitors. Give each list a name so the results show which competitor each domain links to.
- Choose how domains are matched. "Root domain" treats blog.example.co.uk and example.co.uk as the same site. "Exact hostname" keeps subdomains separate.
- Compare the lists. The tool removes protocols, www, paths, ports and repeated rows, takes out every domain already in your list, and counts how many competitors each remaining domain links to.
- Download the CSV. The file contains referring_domain, competitor_count, competitors_linked and priority, ready for a spreadsheet or your outreach tracker.
The tool reports how many rows it accepted and skipped for each list. A skipped row is anything that is not a valid domain or URL; the tool never guesses at one.
Where Do You Get Backlink Data?
Use Ahrefs, Semrush or another backlink provider for competitor referring domains. Google Search Console gives you link data only for sites you have verified, so it can cover your own list but not your competitors'.
- Ahrefs: export the Referring domains report from Site Explorer for each site. Ahrefs also runs its own comparison in its Link Intersect report.
- Semrush: export Referring Domains from Backlink Analytics. Its Backlink Gap tool compares up to five websites and shows a Matches column for each referring domain.
- Google Search Console: in the Links report, the Top linking sites table and the export give you domains linking to your property. Google describes this report as a sample, not a complete list, and notes that some links it shows may since have been removed.
- Other tools: any CSV with a column of domains or URLs will work, including Moz, Majestic or your own spreadsheet.
Using different sources for different sites is possible, but it changes what a gap means. If your list comes from Search Console and your competitors' lists come from a paid index, some "missing" domains may already link to you and simply be absent from the sample. Where you can, export every list from the same provider on the same day.
This tool is not affiliated with Ahrefs, Semrush or Google, and it does not connect to them. You bring the exports; it compares them.
How Are Backlink Gaps Prioritised?
Each missing domain is ranked by how many of your competitors it links to. The labels measure overlap, not link quality.
- High: the domain links to every competitor you entered. With two competitors, a domain shared by both is High.
- Medium: it links to at least two competitors, but not all of them.
- Low: it links to one competitor.
Overlap is a useful starting signal. A site that links to several businesses in your space has shown it is willing to cover the topic, which is the same reasoning Semrush gives for its Matches column. But overlap says nothing about whether the site is relevant, well run or open to linking to you. Five competitors can all share the same low-quality directory.
Which Missing Backlinks Are Worth Pursuing?
Check every domain by hand before you contact it or pay for anything. Open the site and the page that links to your competitor, then ask:
- Relevance: is the site about your industry or your customers' interests?
- Visibility: does the site get search traffic of its own, or does it exist mainly to sell links?
- Context: is the competitor's link inside a real article, a resource list, a directory entry or a sitewide footer?
- Link type: is it a followed link, or marked nofollow, sponsored or ugc?
- How it was earned: was it an editorial mention, a guest post, a partnership, a sponsorship or a paid listing?
- Outbound pattern: does the site link out to dozens of unrelated businesses on every page?
Our list of guest post site red flags covers the warning signs to look for before you pay for a placement. If a placement does cost money, the backlink value calculator lets you test whether it is likely to pay back on your own traffic and conversion numbers.
From Shortlist to Plan
Turn Your Shortlist Into a Link-Building Plan
Keep the backlinks you acquire organised alongside connected Google Search Console data in Backlink Management.
Organise Your BacklinksCan You Run Backlink Gap Analysis Without Paid Tools?
Yes, if you already have usable lists, but competitor data is the limiting factor. This tool compares lists; it does not generate competitor backlink data.
Your own referring domains are free from Google Search Console. Competitor lists are harder: most complete backlink indexes are paid, though several providers offer limited free reports. A spreadsheet can perform the same comparison using COUNTIF formulas, but cleaning domains and comparing several lists becomes more cumbersome as you add competitors. The tool removes that step and handles the clean-up for you.
If you combine several exports before comparing, remove repeated rows first. Our guide to duplicate backlinks in reports explains how to separate repeat imports from genuinely separate links.
What Should You Do After Finding the Gaps?
Shortlist the credible prospects, work out how each competitor earned its link, then choose the right approach for each one.
- Editorial mentions and resource pages: create or improve the page that deserves the link, then pitch the editor.
- Partnerships and associations: check whether you qualify for the same membership, supplier listing or event.
- Guest posts: where the site accepts contributed articles, pitch a topic its readers need. If you prefer to buy a placement on a site you have already vetted, you can compare publishers in a guest post marketplace.
- Skip the rest: drop sites that fail the checks above, however many competitors they link to.
Keep the shortlist somewhere you can update. The free guest post tracker template gives you columns for each placement's agreed details and your later checks.
Frequently Asked Questions
Is the backlink gap analysis tool free?
Yes. You can compare lists and download the CSV without creating a Backlink Management account.
Does the tool crawl my competitors' backlinks?
No. It has no backlink index and does not fetch data from any website. It compares the lists you paste or upload, so you need to export your competitors' referring domains from a backlink tool first.
Where can I get backlink exports?
Export referring domains from Ahrefs, Semrush, Moz, Majestic or another backlink provider. For your own site, the Links report in Google Search Console can be exported for free.
Is Google Search Console data enough?
For your own site it is a useful free source, but Google describes the Links report as a sample rather than a complete list, and it may include links that have since been removed. It cannot show competitors' links, because you can only view properties you have verified.
Will raw Ahrefs and Semrush exports work?
Yes. The tool reads comma- and tab-separated files, including UTF-16 exports such as those Ahrefs produces, and pre-selects a column whose header looks like a referring domain or source URL. You can change the column if it picks the wrong one.
Does the CSV keep metrics such as Domain Rating or traffic?
No. The download lists each missing domain, how many competitors it links to, which ones, and its priority. Metrics from your exports are not carried over, so keep the original files if you want to look them up during vetting.
Why use this if I already pay for Ahrefs or Semrush?
Their built-in gap reports work well when every site is in the same tool. This page helps when your lists come from different sources, such as your own Search Console export against competitor exports, or when you want a plain overlap count you can share without a tool login.
Do my CSV files leave my browser?
No. Files are read and compared in your browser. The tool does not upload, store or send the lists you add, and clearing the page removes them.
Is a domain shared by all my competitors automatically a good prospect?
No. High priority means the domain links to every competitor you entered, nothing more. Check its relevance, traffic, link context and outbound linking before you pursue it.
Bottom line: a backlink gap analysis tells you where to look, not what to buy. Use the overlap count to decide which domains to research first, check each one by hand, and only then decide whether to earn, pitch or pay for a link.
Next Step
Ready to Act on Your Backlink Gap?
Browse available guest post listings, choose a suitable publisher and manage your placement order in Backlink Management.
Sign Up to Browse ListingsSources
- Ahrefs, How to Do a Backlink Gap Analysis (With Template) (read 11 November 2026)
- Semrush Knowledge Base, Backlink Gap (read 11 November 2026)
- Google Search Console Help, Links report (read 11 November 2026)
- Google Search Central, Qualify your outbound links (read 11 November 2026)