Keyword Difficulty Explained: What the Score Actually Measures

Short answer: a keyword difficulty (KD) score estimates how many strong backlinks the pages on Google's first page have. A higher score means the competition is better linked, so you will probably need more links yourself to break in.

What the score measures

Most KD scores, including the one in our Keyword Difficulty Checker, look at the top ten results for a keyword and how many unique websites link to each of them. That is summarised into a number from 0 to 100.

Because it is built from backlinks, KD pairs naturally with a second number: the referring domains you would need to compete. That turns an abstract score into a concrete target.

What the score does not measure

• Search intent. A low-KD keyword where page one is all product pages will not reward a blog post.
• Content quality. If the ranking pages are thin or outdated, a better page can win with fewer links.
• Topical authority. Sites that cover a topic deeply often outrank their link profile.
• Brand bias. Some results favour big brands regardless of backlinks.

This is why you should always look at the actual results with a SERP checker before committing.

A simple way to choose keywords

1. Generate ideas around your product with a keyword generator.
2. Keep only ideas with intent you can genuinely satisfy.
3. Check KD for each, and sort by the lowest difficulty that still has meaningful volume.
4. Open the SERP for your top candidates and look for weak spots: forums, outdated posts, low-authority sites.
5. Write for the winnable ones first; earn links; move up.

Scores are relative

Every SEO tool calculates difficulty differently, so a 30 in one tool is not a 30 in another. Compare keywords against each other using the same tool, and track how your own site's authority grows over time.