You plug a target search term into Ahrefs and see a score of 18, suggesting an easy path to page one. You cross-check the same term in Semrush and find...
You plug a target search term into Ahrefs and see a score of 18, suggesting an easy path to page one. You cross-check the same term in Semrush and find a score of 52, while Moz assigns it a 34. This discrepancy leads marketing teams to waste tens of thousands of dollars chasing competitive terms disguised as easy targets, or abandoning high-value terms based on arbitrary metrics.
Every major SEO platform calculates its keyword difficulty score using a proprietary formula applied to its own proprietary web index. Because no single vendor crawls the entire web identically, their baseline link data differs in size, freshness, and spam filtering. When two tools look at the exact same search engine results page (SERP), they are evaluating two fundamentally different data sets through two different mathematical lenses.
Ahrefs calculates its score almost exclusively on a logarithmic scale of referring domains pointing to the top 10 ranking pages. According to Ahrefs’ official documentation, its formula deliberately ignores on-page SEO, domain-level authority, content quality, and search intent. If the top 10 pages for a search term have few backlinking domains, Ahrefs flags the term as easy, even if those pages belong to multi-billion-dollar brands that dominate the keyword through domain-level strength.
Semrush uses a composite metric called Authority Score alongside link counts, search volume, and SERP feature density. Semrush heavily weighs domain-level strength alongside page-level metrics. As a result, Semrush routinely assigns higher difficulty scores to commercial search terms where enterprise domains rank, even if the specific ranking URLs have zero direct backlinks.
Moz calculates difficulty by weighing Page Authority (PA) and Domain Authority (DA) against link profiles. Moz heavily favors domain-level authority metrics, which leads to higher difficulty scores for broad industry terms.
Because these crawlers operate independently, their link indexes vary wildly. A link that one platform flags as a high-authority editorial mention might be filtered out as low-value web spam by another platform’s crawler infrastructure.
| SEO Tool | Primary Formula Inputs | Typical Bias & Blindspots |
|---|---|---|
| Ahrefs | Raw number of referring domains pointing directly to the top 10 ranking URLs. | Ignores domain authority, content intent, and internal link equity. Underestimates difficulty on brand-dominated SERPs. |
| Semrush | Page-level backlinks, Domain Authority Score, search volume, and SERP features. | Overestimates difficulty on high-volume terms where top pages have weak link profiles but high site authority. |
| Moz | Weighted combination of Page Authority (PA) and Domain Authority (DA). | Heavily skews toward domain strength. Overestimates difficulty for niche terms dominated by large media sites with thin content. |
| Serpstat | Number of page backlinks, domain rank of top competitors, and on-page keyword density. | Underweights non-link ranking signals like user engagement patterns, search intent layout, and SERP feature displacement. |
A difficulty score is an absolute metric forced onto a relative ecosystem. A keyword difficulty score of 30 out of 100 carries no actionable meaning until evaluated against your specific site’s baseline authority and topical footprint.
Consider two different websites targeting the exact same query with a tool-assigned difficulty score of 30:
Site authority is not restricted to off-page link profiles; topical relevance plays an equal role. If your domain features 50 comprehensive guides covering supply chain logistics, Google recognizes your site as a topical authority in that vertical. You can easily outrank a general business news outlet with a DR of 85 for a logistics term, even if the news outlet has vastly superior overall link metrics.
Evaluating raw difficulty scores without factoring in your site’s domain strength, existing topical authority, and technical health guarantees inaccurate resource forecasting. A term labeled “easy” by a software tool is often impossible for an authoritative site that lacks vertical relevance.
The standard advice repeated in mainstream SEO guides is simple: filter your keyword database for difficulty scores under 20, write a 1,500-word article, and claim easy search traffic. Following this strategy in 2026 is one of the fastest ways to burn through a content budget with zero return.
Popular advice fails because third-party software tools cannot interpret search intent, SERP layout dynamics, or user engagement requirements. Here is why targeting low-difficulty terms frequently backfires:
SEO tools routinely assign low difficulty scores to queries where the top 5 ranking results consist of forum threads on Reddit or Quora, video embeds, or user-generated reviews. Ahrefs or Moz registers a low score because individual forum threads rarely have direct backlink profiles. However, Google intentionally ranks these pages because users want community discussions, not an SEO-optimized corporate blog post. Publishing a standard article for these queries yields zero top-tier rankings because your format conflicts with user intent.
A search query can carry a difficulty score of 10 while being functionally useless for driving organic traffic. If a SERP contains an AI Overview, a local 3-pack, a video carousel, four sponsored ads, and a featured snippet, the actual organic click-through rate (CTR) for position 1 can drop below 4%. The keyword is technically easy to rank for, but the traffic yield does not justify the publishing cost.
To determine true search difficulty, ignore the aggregate score in your software suite and analyze the live search results directly. A accurate manual SERP evaluation requires reviewing four specific components.
Look at the domain strength of the top 5 organic results. Compare their metrics against your site’s baseline using the following benchmarks:
Do not rely on the total backlink number shown in table views. Open the link profiles for the top 3 ranking URLs in your backlink analysis tool and evaluate link quality:
Identify the exact content format Google favors for the target query. Categorize the top 5 results into structural types:
If the top 4 organic positions are occupied by free web tools, writing a 3,000-word article will fail to rank, regardless of how many backlinks you build to it. You must match the format required by the search engine.
Search engine results pages contain structural vulnerabilities that indicate genuine ranking opportunities, even when software tools report high difficulty scores. Look for the following green flags:
To scale your organic strategy efficiently, replace arbitrary tool scores with an internal difficulty matrix calibrated to your resource constraints, site authority, and content operations.
Categorize prospective keywords into three execution tiers based on manual SERP evaluations and direct operational costs:
Evaluating keywords through an internal cost-and-effort framework allows marketing leads to allocate capital based on realistic ranking requirements, avoiding the trap of relying on vendor-specific difficulty scores.
Want the measurement, not the pitch?
Send us your domain. We run the baseline on your category prompts and send back the raw answers alongside the score — you can check our working.
Đội ngũ chuyên gia Vidco Group sẵn sàng đồng hành cùng bạn
Bước 1 / 4
Chúng tôi sẽ liên hệ trong vòng 2 giờ làm việc.