10 Best Backlink Checkers [2026]: Index Size & Accuracy

Short answer: Ahrefs is the best backlink checker, with one of the largest and freshest link indexes and the clearest interface. Semrush is a close second with a huge index and strong toxicity tools, and Majestic remains the link specialist with Trust Flow. SEO Runway is not index-first. It's the right pick if you want your backlink profile, new and lost links and anchor-text risk next to rankings and audits, but for link research depth, choose one of the top three.

Disclosure: SEO Runway is our product. We ranked it using the same criteria as every other tool, and noted where others do better.

Quick picks

• Best overall: Ahrefs
• Best for toxicity audits: Semrush
• Best link specialist: Majestic
• Best value: SE Ranking
• Best free check: Ahrefs or Moz free tools

Backlink checkers compared

*Approximate; verify.

How we chose these tools

We compared each tool's published features, plans and documentation on six criteria: index size and freshness, authority metric, anchor data, new and lost tracking, competitor comparison, and price.

1. Ahrefs: best overall

Verdict: a huge, fresh index and the clearest way to explore links.

Pros: index; UI; Link Intersect.

Cons: price; usage limits.

2. Semrush: best for toxicity audits

Verdict: a large index with backlink audit and toxicity scoring.

Pros: audit tools; gap analysis.

Cons: toxicity scores need human judgement.

3. Majestic: best link specialist

Verdict: a link-only tool with Trust Flow and topical metrics.

Pros: link focus; historic index.

Cons: no wider SEO toolkit.

4. Moz Link Explorer: best known metric

Verdict: Domain Authority, widely recognised by clients.

Pros: DA familiarity.

Cons: a smaller index.

5. SE Ranking: best value

Verdict: solid backlink data inside an affordable suite.

Pros: value.

Cons: a smaller index.

6. SEO Runway: best backlink profile inside an all-in-one

Verdict: your backlink profile with new and lost links and an anchor-text risk check, next to rankings, audits and a link-building pipeline with outreach templates.

Pricing: included with Core SEO from $49/month; 14-day free trial. See plans.

Pros: link health in context; outreach pipeline included.

Cons: a smaller index than Ahrefs, Semrush or Majestic, so not ideal for deep competitor link research.

7. Serpstat: budget all-rounder

Verdict: backlinks within a cheap suite.

Pros: price.

Cons: index size.

8. SEO PowerSuite SpyGlass: best desktop option

Verdict: a desktop backlink tool with its own index.

Pros: one-off licensing.

Cons: desktop app.

9. Ubersuggest: cheapest

Verdict: basic backlink data cheaply.

Pros: price.

Cons: depth.

10. LinkResearchTools: best for link risk forensics

Verdict: deep link risk analysis from many sources.

Pros: forensics.

Cons: price; complexity.

Why backlink counts differ between tools

• Each tool crawls the web separately, with its own crawl budget and priorities.
• Different freshness: some keep lost links longer than others.
• Different counting: links vs referring domains, and how redirects and nofollow are handled.
• Different filters for spam and duplicates.

No tool sees every link Google sees. Pick one, and track referring-domain trends over time. [Optional: add your own three-site index test here.]

More backlink guides

• Link building tools (prospecting and outreach)
• Backlink monitoring tools (new, lost and anchor alerts)
• SEO audit tools

Frequently asked questions

Which backlink checker has the biggest index?

Ahrefs, Semrush and Majestic all report very large indexes and trade places depending on how size is measured. Test them on your own and competitors' sites.

Why do tools show different backlink numbers?

Each tool crawls, stores and filters links differently. Compare referring domains over time within one tool rather than across tools.

Is Domain Authority a Google metric?

No. DA (Moz), DR (Ahrefs), Authority Score (Semrush) and Trust Flow (Majestic) are third-party estimates.

Can I check backlinks for free?

Yes, partially. Ahrefs and Moz offer free checkers with limited results, and Google Search Console shows links Google knows about for your own site.

The bottom line

• Best overall: Ahrefs.
• Link audits: Semrush.
• Link specialists: Majestic.
• Value: SE Ranking.
• Link health next to rank and audit in one platform: SEO Runway.

Start a 14-day free trial of SEO Runway to check your backlink profile and anchor risk, or see the SEO workspace.