Historically, SEOs targeted a specific density (2–5 %) to signal topical relevance. Modern search engines use language models that understand synonyms and intent, so density is no longer a ranking dial you can tune.
It is still a useful diagnostic. A density near zero means you're writing about the topic without naming it; a density above ~6 % often reads as keyword stuffing to both readers and algorithms.
Aim for natural prose that names the primary term in the title, first paragraph, one H2, and once per few hundred words after that.