Why Word Frequency Isn't the Same as Keyword Density
Two tools that count words for very different reasons, and why using the wrong one gives a misleading answer to the question you actually had.
Published May 1, 2026
Both tools count how often words appear in a text. That surface similarity hides a real difference in what question each one is actually trying to answer, and using the wrong one produces a technically-correct but not-actually-useful result.
Keyword density is asking an SEO question
It filters out common stopwords (the, is, and) to focus on meaningful search terms, because the question it's answering is specifically about search optimization: is a target keyword appearing often enough to signal relevance, or so often it looks like stuffing? Stopwords are noise for that particular question, so removing them is the right call.
Word frequency is asking a writing question
It counts every word, including the ones keyword density filters out, because the question here is different: does this piece of writing feel repetitive to an actual reader? A paragraph that overuses "just," "actually," or "very" has a real writing problem that a stopword-filtered keyword tool would never surface, since those exact words are the ones it's designed to ignore.
Picking the right one for the actual question
Optimizing a page for a target search term calls for keyword density. Editing a draft to catch overused filler words, checking whether your own writing leans on the same handful of words too often, calls for word frequency instead. They look similar enough to reach for interchangeably, but they're built to answer genuinely different questions.