What is Keyword Density?
Keyword density is the percentage of times a keyword or phrase appears on a web page compared to the total number of words on the page. In the past, SEOs would stuff pages with keywords to rank higher. Today, Google's AI algorithms penalize "keyword stuffing."
What is a good density?
There is no perfect number, but generally, a keyword density between 0.5% and 2.5% is considered natural. If your primary keyword density is over 3%, you run the risk of looking spammy. Use synonyms and semantic variations (LSI keywords) instead of repeating the exact same phrase.
Why analyze N-Grams?
Google looks at phrases, not just individual words. If you are writing about "SEO tools," the phrase "SEO tools" (a 2-gram) matters more than the individual words "SEO" and "tools" appearing separately.