Keyword difficulty (KD) is a third-party estimate of how hard it may be to compete for a search query. It is useful for screening a keyword list, but it is not a Google metric and it is not a verdict on whether your page can rank.
A neat score is convenient in a spreadsheet. The publishing decision is less tidy. You still need to check what the tool measures, what Google is actually showing for the query, how strong the ranking pages are, and whether your site has a credible reason to compete.
What Keyword Difficulty Can Tell You, and What It Cannot
Use KD to estimate competitive resistance, not to decide whether a keyword is good. Difficulty and value are different questions. A low-KD query may have little relevance to your audience, while a difficult query may still deserve attention because it sits at the centre of an important topic.
This page focuses on one part of the wider keyword research process: deciding how difficult a query looks and whether that difficulty changes what you should do next. Search volume, keyword discovery, mapping and broader prioritisation belong elsewhere in the research workflow.
Google’s guidance on third-party SEO tools and advice makes an important boundary clear: third-party tools do not have access to Google’s internal ranking data. Their scores and predictions are their own estimates. That does not make KD useless, but it does mean the number needs interpretation.
Why Keyword Difficulty Scores Differ Between SEO Tools
There is no universal KD formula. Two tools can score the same query differently because they use different data, weighting and definitions of difficulty. Treating a 35 in one platform as equivalent to a 35 in another creates false precision.
| Metric | What the provider says it measures | What to remember |
|---|---|---|
| Ahrefs KD | Difficulty of reaching the top 10, calculated from the number of referring domains pointing to the current top 10 organic pages. | Ahrefs states that its KD does not include on-page SEO factors, so the score is deliberately link-focused. |
| Semrush KD | A 0 to 100 estimate based on the search results and backlink profiles of pages already ranking in Google’s top 10. | The general score describes competitive difficulty for the query, not the circumstances of one particular site. |
| Semrush PKD | A domain-specific estimate that considers thematic relevance, topic competition and metrics from the entered domain and competitors in the SERP. | PKD answers a different question from general KD, so the two figures should not be treated as interchangeable. |
The practical consequence is simple: choose a tool for consistent comparison, learn what its score represents, and then use the live SERP to test the assumptions behind that score.
How to Check Keyword Difficulty in Practice
Start with the tool score because it is fast. Do not stop there. A useful difficulty review moves from the metric to the SERP and then back to your own site.
- Record the score and its context. Note the SEO tool, target country or database, and the date of the check. If you revisit the keyword later, you need to know whether you are comparing like with like.
- Confirm the dominant page type and intent. Look at the top results. If Google is mainly showing product pages, tools, local results or comparison pages, an informational article may be the wrong asset even when KD looks low. The separate guide to search intent covers that classification in more depth.
- Inspect the ranking pages, not just their domains. Check whether the pages themselves have substantial referring-domain support, whether they answer the query directly, whether the information is still current, and whether the result set leaves a genuine content gap.
- Check the search-result layout. Ads, AI features, maps, video results, shopping units and other result types can change how much visible space remains for a conventional organic result. A keyword can be rankable and still offer less click opportunity than its search volume suggests.
- Compare the query with your site’s position. Ask whether you already cover the topic, can support the page with relevant internal links, and can publish something that fits the dominant intent without stretching beyond your expertise.
None of these checks produces a perfect probability of ranking. Together, they tell you more than a single score because they separate link competition, intent fit, page quality, SERP layout and site readiness.
Read the SERP Before You Trust the Number
The most useful manual check is not ‘Are these domains famous?’ It is ‘What would my page have to beat, and on what grounds?’
A page-type mismatch can make a low score misleading
If the first page is dominated by category pages and tools, publishing a basic article is unlikely to solve the mismatch. The problem is not that your article needs more words. It is that you are proposing the wrong page type for the query.
Strong links and a weak answer are different signals
A SERP can contain heavily linked pages that do not answer the query particularly well. That may create an editorial opportunity, but it does not erase the link gap. Equally, lightly linked results are not automatically easy if the intent is tightly satisfied by specialised pages you cannot credibly reproduce.
Do not reduce the review to brand strength
Large brands can make a SERP look intimidating, but brand size alone does not tell you why a particular page ranks. Look at the ranking URL, page format, topical relevance, links, freshness and usefulness. A broad authority metric is supporting context, not a substitute for inspecting the result.
Turn the Difficulty Check Into a Content Decision
The point of checking KD is not to label a keyword ‘easy’ or ‘hard’. It is to decide what level of commitment makes sense.
Target it now
This is the strongest case when the query fits your audience, the dominant result type matches the page you can create, the ranking pages leave room for a clearer or more useful answer, and your site already has relevant topical support. A lower tool score may reinforce that decision, but it should not be the reason for it.
Build support first
A difficult keyword can still be strategically important. If the SERP is strong but the topic belongs on your site, strengthen the surrounding content, improve relevant existing pages, and create a sensible internal linking structure before expecting one new page to do all the work. This is a sequencing decision, not a promise that support content will overcome every competitive gap.
Deprioritise it
Leave the keyword alone, at least for now, when the intent does not fit your offer, the required page type is outside your site, the likely value does not justify the work, or the SERP gives you no credible way to add something better. Low KD does not rescue a poor target.
That distinction keeps this supporting page narrow: the broader keyword-research guide covers how keywords are discovered and prioritised, while this page answers a more specific question, namely how much weight to give competitive difficulty before committing to a target.
