Keyword Difficulty (KD)
A metric from SEO tools estimating how hard it is to rank for a keyword. Useful for prioritisation, but take it with a grain of salt - the real difficulty depends on your specific site and competition.
Why It Matters
Keyword difficulty scores help you prioritise which keywords to target. Going after a KD 95 keyword when your site is brand new is a waste of resources. Starting with KD 20-30 keywords and building up makes strategic sense.
But KD scores are estimates, not facts. Each tool calculates them differently (Ahrefs focuses on backlinks, Moz includes other factors, Semrush uses its own formula). The actual difficulty of ranking depends on your specific domain authority, topical relevance, content quality, and the competitive landscape - none of which a single number captures.
In Practice
Use keyword difficulty as one input in your prioritisation, not the only input. A low KD keyword with no search volume isn't worth targeting. A high KD keyword that perfectly matches your business might be worth a long-term content strategy.
Compare KD scores within the same tool - don't compare Ahrefs KD to Semrush KD, they use different scales. Look at the actual top-ranking pages for a keyword to assess difficulty - are they massive authority sites or smaller sites you could realistically compete with?
Target a mix of difficulties. Quick wins from low KD keywords build traffic while you work toward higher KD terms over months.
Related Terms
Glossary
Keyword Research
Finding what your audience searches for - the foundation of every SEO strategy.
Glossary
Long-Tail Keyword
Longer, more specific search queries - lower volume but higher intent and easier to rank for.
Glossary
Domain Authority (DA)
Moz's third-party metric predicting ranking potential - useful, but not a Google factor.
Glossary
Topical Authority
How comprehensively your site covers a subject - depth beats breadth for rankings.
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