What this tool checks
I pull the visible text off the page you give me, strip out the scripts, styling and the usual navigation and footer noise, then count how often every word and phrase appears. You get three tables: single keywords, two-word phrases and three-word phrases, each ranked by how many times they show up and what share of the total text they take up.
Why keyword density still matters
Density is not a magic number you chase, and I would never tell you to cram a phrase in until you hit some target. What it does tell you is what a page is genuinely about. If the words you want to rank for barely appear, or a completely off-topic phrase dominates, that is a signal something has drifted. It is the fastest way to sense-check whether a page is focused or waffling.
How I use this in real work
Before I rewrite a page I run it through here to see what it currently emphasises, then compare that against what the page should be about. It is also handy for auditing competitors: scrape their top-ranking page and you can see the vocabulary they lean on. If you want me to turn these signals into a proper plan, book a call and we can go through it together.