What is keyword density?
Keyword density is the percentage of times a specific word or phrase appears in a piece of content relative to the total word count. If an article is 1,000 words and contains the word "running" 15 times, the keyword density for "running" is 1.5%. Historically, SEO practitioners tried to optimise keyword density — keeping target keywords at a specific percentage thought to signal relevance to search engines. This approach has become largely obsolete as search algorithms have become more sophisticated, but understanding keyword frequency remains useful for content quality and natural language optimisation.
How the analyser works
Paste any text — a blog post, web page content, product description, article draft — into the input area. The analyser tokenises the text into words, filters out stop words (common words like "the", "a", "and" that carry no topical signal), and counts the frequency of every remaining word and multi-word phrase. Results are shown in a sortable table with frequency counts and density percentages, ranked by frequency with a visual bar chart column.
Single words, 2-word phrases, and 3-word phrases
The three tabs separate analysis by n-gram length. Single words reveal which individual terms dominate your content. Two-word phrases (bigrams) show which paired terms you use most, which often reveals natural keyword clusters — "search engine", "content marketing", "email list". Three-word phrases (trigrams) surface more specific topic signals — "search engine optimisation", "long tail keywords", "conversion rate optimisation". The multi-word phrase tabs are particularly useful because they reveal whether your content naturally uses the complete keyword phrases your audience searches for.
The density colour coding
Density values above 4% are shown in red — high enough to potentially appear unnatural or keyword-stuffed to both readers and algorithms. Values between 2.5% and 4% are shown in amber — worth checking whether the repetition reads naturally. Values below 2.5% are shown in the accent colour — generally healthy. There is no universal "correct" keyword density, but these thresholds flag content worth reviewing.
Stop word filtering
Stop words are extremely common words (a, an, the, and, or, but, in, on, at, to, for, of, with, by, from, is, was, are, were, and so on) that appear in virtually every piece of text without indicating topical relevance. Filtering them out produces a cleaner frequency table showing only the content words that carry meaning. Disable stop word filtering if you need to see the complete word frequency including common words — useful for style analysis or detecting repetitive sentence patterns.