Backlinks remain one of Google’s most important ranking signals — and if you’re serious about SEO, you need a tool that can actually see who’s linking to you, who’s linking to your competitors, and which links might be quietly hurting your rankings.
Semrush’s backlink database is genuinely impressive: 43 trillion backlinks indexed, making it one of the largest link intelligence datasets in the world. For competitive analysis, toxic link auditing, and link-building prospecting, it’s a remarkably capable toolkit.
In this review, we cover every backlink tool inside Semrush, how to use them effectively, what Authority Score actually means, and — honestly — where Ahrefs still edges Semrush out for pure backlink depth. For an overview of all Semrush features, see our Semrush Review 2026.
Semrush’s Backlink Tools: What’s Included?
Semrush doesn’t give you one backlink tool — it gives you four separate, purpose-built tools that each tackle a different part of backlink analysis:
| Tool | Purpose |
|---|---|
| Backlink Analytics | Analyze any domain’s full backlink profile |
| Backlink Audit | Identify toxic links; generate disavow files |
| Link Building Tool | Find outreach prospects; manage campaigns |
| Backlink Gap | Compare your profile against up to 5 competitors |
All four are included on every paid plan (Pro, Guru, Business) — for plan pricing details, see our Semrush pricing guide. Together, they cover the full link-building lifecycle: research → audit → outreach → gap analysis. Let’s look at each one in detail.
Semrush Backlink Analytics: Analyzing Any Domain’s Links
Backlink Analytics is the core research engine. Enter any domain or URL and you get a complete picture of its backlink profile — including data from Semrush’s 43 trillion link database.
What you see in Backlink Analytics:
- Total backlinks: The full count of inbound links pointing to the domain
- Referring domains: How many unique domains are linking in (more meaningful than raw backlink count)
- Authority Score: Semrush’s proprietary domain strength metric (0–100)
- New and lost links: Track link acquisition velocity and spot sudden drops
- Anchor text distribution: See what phrases sites use when linking — reveals over-optimization or natural link profiles
- Top referring pages: Which of the target’s pages attract the most links
- Referring domains by country, IP, and TLD: Useful for spotting link spam patterns
How to use it for competitor research:
This is where Backlink Analytics becomes genuinely valuable. Enter a competitor’s domain and you can immediately see which sites are linking to them. Filter by Authority Score to find only high-quality referring domains. Sort by “New” links to see which sites have recently linked to competitors — often the highest-probability outreach targets, because those publishers are actively covering your space right now.
For example: if you enter your closest competitor and sort referring domains by Authority Score descending, you’ll find the 20–30 highest-value sites already linking to them. Those are your prioritized outreach targets.
Authority Score Explained
Authority Score is Semrush’s proprietary metric for measuring the overall SEO strength of a domain or URL. It runs on a 0–100 scale, with higher scores indicating stronger domains.
How Authority Score is calculated:
According to Semrush, Authority Score is based on three inputs:
- Backlink data — the quality, quantity, and authority of links pointing to the domain
- Organic traffic signals — estimated search traffic the domain receives
- Spam signals — indicators of unnatural, purchased, or low-quality link patterns
This multi-factor approach is why Authority Score can change even when your link count stays the same — if your organic traffic signals improve (or decline), your score moves with it.
How it differs from Ahrefs DR and Moz DA:
| Metric | Provider | Basis |
|---|---|---|
| Authority Score | Semrush | Backlinks + organic traffic + spam signals |
| Domain Rating (DR) | Ahrefs | Backlink profile quality only |
| Domain Authority (DA) | Moz | Backlink-based machine learning model |
Ahrefs’ Domain Rating is a purer measure of link profile strength — it intentionally ignores traffic signals. Moz DA uses a machine learning model predicting ranking ability. Semrush’s Authority Score is the most comprehensive in theory, but also the most opaque in methodology.
Is Authority Score reliable?
Directionally, yes. Sites with scores above 70 reliably correspond to high-authority properties. The metric is useful for quick competitive benchmarking and for filtering link prospects by quality. However, Authority Score should be treated as a relative signal, not an absolute truth — and like all third-party metrics, it doesn’t perfectly predict where any specific page will rank. Use it as one data point, not the only one.
Semrush Backlink Audit: Finding Toxic Links
The Backlink Audit tool is built around a specific use case: identifying links that might be harming your rankings and generating a disavow file to submit to Google.
How it works:
Semrush evaluates every link pointing to your domain across 50+ parameters, including:
- The toxicity score of the referring domain
- Anchor text patterns (keyword-stuffed anchors are a red flag)
- Link placement context (footer spam, comment spam, widget links)
- Referring domain age and history
- IP neighborhood quality
Each backlink gets a Toxic Score between 0–100. Links above a certain threshold get flagged as “Toxic” or “Potentially Toxic” and grouped for review.
Generating a disavow file:
Once you’ve reviewed flagged links and confirmed which ones to reject, Semrush generates a properly formatted disavow file ready to upload directly to Google Search Console. The workflow is:
- Run the Backlink Audit on your domain
- Review the Toxic and Potentially Toxic lists
- Check each link manually — many false positives exist
- Mark confirmed toxic links for disavowal
- Export the disavow file and upload to Google Search Console
When you actually need to disavow links:
Here’s the honest answer: for most sites, you don’t. Google has become very good at algorithmically ignoring low-quality links rather than penalizing them. The disavow tool is primarily useful when:
- You’ve received a manual penalty from Google (you’ll see it in Search Console)
- You’ve recently been involved in link schemes and need to clean up
- You acquired a domain with a historically spammy link profile
Google’s own guidance as of 2026 is cautious about aggressive disavow use — removing links that Google was already ignoring can sometimes cause more harm than good. Use the Backlink Audit output as an investigative tool first; disavow only when you have a real problem, not just a list of low-quality links that were never affecting you.
Semrush Link Building Tool
The Link Building Tool is Semrush’s attempt to bring outreach management inside the platform. After entering your domain and target keywords, Semrush suggests link-building prospects — domains that are contextually relevant and don’t already link to you.
What it offers:
- Prospect discovery: Based on your keywords and competitor backlink profiles
- In-tool outreach: Send email outreach directly from within Semrush via connected email account
- Progress tracking: Track which prospects you’ve contacted, which responded, and which links went live
- Integration with Backlink Analytics: Prospects are scored using Authority Score so you can prioritize
Limitations to be aware of:
The Link Building Tool is functional but basic by specialist standards. Dedicated outreach tools like Pitchbox, BuzzStream, and Respona offer significantly more sophisticated campaign management, email personalization, follow-up automation, and CRM-style contact tracking. If link building is a high-volume, systematic part of your SEO strategy, you’ll likely outgrow Semrush’s built-in outreach features quickly.
For occasional, targeted outreach campaigns — especially at the research and prospecting stage — it works well. For agencies running link building at scale, treat it as a prospecting aid, not a full outreach platform.
Semrush Backlink Gap Tool
The Backlink Gap tool answers one of the most valuable questions in SEO: which sites link to my competitors but not to me? Those are your highest-probability link opportunities — publishers already interested in your topic who haven’t yet discovered your content.
How to use Backlink Gap:
- Enter your domain as the primary target
- Add up to 4 competitor domains for comparison
- Semrush shows referring domains broken down by which combination of sites they link to
- Filter to “Strong” or “Best” — these are high-authority domains linking to multiple competitors but not you
- Export the list and prioritize by Authority Score
Reading the Backlink Gap output:
The tool uses a Venn-style overlap visualization. Look for referring domains in the “competitors only” sections — those sites have demonstrated interest in your space (by linking to multiple competitors) but haven’t linked to you yet. A referring domain linking to three of your competitors is significantly more likely to link to you than a cold outreach target with no established pattern.
This tool is particularly useful when entering a new vertical or planning a major content investment. Before you create a new resource, run Backlink Gap to see which domains are actively linking in that topic area — then create content those specific publishers would find valuable.
How to Run a Full Backlink Analysis in Semrush (Step-by-Step)
Here’s a practical 5-step workflow for using Semrush’s backlink tools together:
Step 1: Baseline your own profile Open Backlink Analytics and enter your own domain. Note your Authority Score, total referring domains, and anchor text distribution. Save this as your benchmark.
Step 2: Analyze top competitors Enter your 2–3 closest competitors in Backlink Analytics. Compare their Authority Scores and referring domain counts to yours. Look at their top referring pages — what types of content attract the most links?
Step 3: Check new and lost link velocity In your own Backlink Analytics report, filter to “New” and “Lost” links over the past 30 days. Sudden drops in referring domains can indicate Google penalties, domain removals, or link rot that needs addressing.
Step 4: Run the Backlink Audit Set up a Backlink Audit for your domain. Review Toxic and Potentially Toxic flagged links. Don’t mass-disavow — verify each link manually before adding it to your disavow file.
Step 5: Run the Backlink Gap Use Backlink Gap with your top 3–4 competitors. Export the “Best” and “Strong” opportunity domains. These become your link-building prospect list, already pre-qualified by proven relevance to your space.
Full workflow time: 2–3 hours for a thorough initial analysis; 30 minutes monthly for maintenance monitoring.
Semrush Backlinks vs Ahrefs: Which Is More Accurate?
This is the question SEO professionals argue about constantly — and it deserves a straight answer.
The numbers:
- Semrush: 43 trillion backlinks indexed
- Ahrefs: Crawls over 8 billion web pages per day; widely regarded as having one of the most accurate and freshest link indexes in the industry
The honest comparison:
Ahrefs edges Semrush on pure backlink data quality. Ahrefs’ crawler is faster at discovering new links and more reliable at identifying when links have been removed. This matters in practice: when doing a disavow audit or trying to understand whether a specific link is still live, Ahrefs’ data tends to be more current.
Semrush’s 43 trillion link database is genuinely large — one of the largest in the world — but raw database size doesn’t automatically equal freshness or accuracy. Industry consensus among link-building specialists consistently rates Ahrefs’ link data as more dependable for granular daily work.
Where Semrush holds its own:
For competitive research (not daily link monitoring), Semrush’s backlink data is more than adequate. Its 43T database catches links that matter. The Authority Score, combined with organic traffic signals, provides useful context that Ahrefs’ DR metric doesn’t include. And the integrated workflow across Backlink Analytics → Backlink Audit → Link Building Tool → Backlink Gap is genuinely convenient.
The verdict:
For teams where backlink analysis is a primary daily activity — link builders, penalty recovery specialists, agencies running active outreach campaigns — Ahrefs is the stronger choice for backlink data.
For teams that use backlink analysis as one component of a broader SEO workflow (alongside keyword research, rank tracking, and site auditing), Semrush’s integrated approach delivers more value overall.
→ See our full head-to-head: Semrush vs Ahrefs 2026
Semrush Backlink Checker Limitations
Being honest about what Semrush’s backlink tools don’t do well:
1. Data freshness vs. Ahrefs As discussed above, Ahrefs’ crawler updates link data faster. For time-sensitive link monitoring, this difference matters.
2. Authority Score methodology is opaque Semrush hasn’t fully disclosed the exact weighting behind Authority Score’s inputs. This makes it harder to predict why scores change or to diagnose specific changes in your score.
3. Outreach tool is basic The built-in Link Building Tool is convenient for prospecting but falls short of dedicated outreach platforms for high-volume link building campaigns. Email personalization, follow-up sequences, and CRM functionality are all limited.
4. False positive rate in Backlink Audit Semrush’s toxic score flags a meaningful number of links that pose no real risk. The audit output requires careful manual review — treating it as an automated disavow recommendation would be a mistake.
Is Semrush Worth It for Backlink Analysis?
For all-round SEO work: yes. If you’re using Semrush for keyword research, rank tracking, competitor analysis, and backlinks together, the backlink suite adds significant value without requiring a separate subscription. The 43T database is large enough to power serious competitive research, the Backlink Gap tool is excellent, and the integrated workflow is efficient.
For link building as your primary activity: consider Ahrefs. If your day-to-day work revolves around link prospecting, outreach, and monitoring — and you need the most accurate, freshest link data available — Ahrefs’ backlink toolset is sharper. Many SEO professionals who run active link-building campaigns use Ahrefs specifically for this reason.
The good news: for most marketing teams that aren’t running industrial-scale link building, Semrush’s backlink tools are more than sufficient. And having everything — keyword research, site audit, competitor intel, and backlinks — in one platform has real operational value.
Related: Semrush Review 2026 | Semrush Pricing 2026 | Allable vs Semrush
FAQ
How many backlinks does Semrush have in its database?
Semrush has 43 trillion backlinks indexed in its database as of 2026. This makes it one of the largest backlink indexes in the world, covering billions of referring domains across all major markets and languages.
What is Semrush Authority Score?
Authority Score is Semrush’s proprietary metric for measuring a domain’s overall SEO strength. It runs on a 0–100 scale and is calculated using three inputs: the quality and quantity of backlinks pointing to the domain, estimated organic search traffic, and spam signals. A score above 70 generally indicates a high-authority domain; below 20 is typically low-authority. Unlike Ahrefs’ Domain Rating, Authority Score factors in traffic data alongside backlink quality.
Is Semrush good for backlink analysis?
Yes — Semrush is a capable backlink analysis tool for most SEO use cases. Its 43T database, Backlink Analytics, Backlink Audit, and Backlink Gap tools cover competitive research, toxic link identification, and link opportunity discovery effectively. For pure backlink depth and data freshness on daily link monitoring, Ahrefs is generally considered the stronger option. For all-round SEO work that includes backlinks as one component, Semrush is an excellent choice.
Semrush vs Ahrefs for backlinks — which is better?
Ahrefs is the better choice for backlinks specifically. Its crawler updates data more frequently and its link index is widely regarded as more accurate for granular link monitoring and outreach work. Semrush’s 43T database is larger in raw count, but Ahrefs wins on data freshness and reliability. For broader SEO work beyond backlinks, Semrush’s wider toolkit (keyword research, PPC analysis, site audit) gives it an advantage overall.
Can Semrush help me disavow bad links?
Yes. Semrush’s Backlink Audit tool identifies potentially toxic links using 50+ parameters and generates a properly formatted disavow file ready for Google Search Console upload. However, be cautious: Google has become very good at ignoring low-quality links algorithmically, and unnecessary disavowal can sometimes cause harm. Use the tool to investigate suspicious link patterns, but only disavow when you have a confirmed manual penalty or clear evidence of a problematic link scheme.
Is Semrush backlink data accurate?
Semrush’s backlink data is accurate enough for competitive research, link gap analysis, and general link profile monitoring. For daily link monitoring where data freshness is critical — such as tracking whether specific links have gone live or been removed — Ahrefs tends to be more reliable. For most teams, Semrush’s accuracy level is more than sufficient for strategic backlink work.
Last updated: April 2026 | Data sourced from Semrush.com official documentation and confirmed platform features | All metrics subject to change — verify current database stats directly with Semrush before citing.