Optimize Your Content with Data, Not Guesswork

WDF*IDF (Within Document Frequency * Inverse Document Frequency) is a mathematical formula used in SEO to analyze and optimize content by evaluating how terms are weighted within your document compared to other ranking pages on the web.

WDF*IDF emerged as a more sophisticated alternative to keyword density, which often led to over-optimized, barely readable content. This approach helps you create naturally flowing content while maintaining optimal term distribution.

WDF*IDF measures how often specific terms appear in your content (Within Document Frequency) and compares that frequency with how often those terms appear in other pages covering the same topic (Inverse Document Frequency). SEOLAXY© WDF*IDF tool visualizes this comparison, showing which terms are underused, balanced, or overused.

It measures how often each term appears within your content (WDF) and how common it is across the top-ranking competitor pages (IDF). Together, they highlight which terms are statistically relevant for a given topic.

It helps you understand how well your content reflects the terminology and topic coverage found in top-ranking pages. By using this insight, you can make your content more complete and relevant, without relying on keyword repetition.

WDF*IDF is based on the TF-IDF formula used in information retrieval to measure how important a term is across a set of documents. It adapts that idea for SEO by adjusting how term frequency is calculated. WDF*IDF measures the relative weight of a term within one document (WDF) and compares it to how common it is across other pages (IDF). In short, it applies the TF-IDF concept specifically to content optimization.

Keyword density only measures how often a word appears in your own text. WDF*IDF compares your content with other top results, making it much more useful for identifying topical relevance rather than repetition.

No. WDF*IDF is not part of Google's ranking algorithm. It's a diagnostic method that helps you understand term usage patterns among high-ranking pages.

WDF*IDF analysis is most useful when creating new, in-depth content, updating or refreshing existing pages, and checking how your text aligns with the terminology used in current top search results.

Yes. You can analyze any URL or just a keyword to compare content performance against real search results.

The WDF*IDF tool is available to SEOLAXY members. A SEOLAXY monthly membership includes gems that you can use not only for WDF*IDF analyses but also to unlock other content within the platform such as checklists, ticket templates, masterclass lessons, and workshops.

Trial users can run one analysis to see how the tool works before upgrading to a full membership.

One WDF*IDF analysis costs 27 gems. Running the same analysis again using the redo option costs 17 gems.