What exactly is the density of a keyword? It's all about dosage. The more often a keyword appears on a website's page, the higher its density. To accurately assess this density, reduce the number of repetitions of a keyword to the total number of words in the page. If the same keyword is repeated three times in a 300-word page, the density index will be 3%.
"Plenty of goods never harms." But does this proverb also apply to keywords? In other words, is the amount of repetition of a keyword synonymous with quality referencing? It is doubtful… Because if density has long had an impact on SEO (the more you repeat a keyword in a page, the better it went back in search engine results), this is no longer the case at present. Google now recommends a keyword density of between 2 and 7 percent. And beyond 10% density index, a site may be penalized compared to its competitors. Bludgeoning a keyword at every end of sentence, for example once every ten words – is sure to arouse the distrust of Google's indexing robots. And above all, it will not be pleasant to read for Internet users. But it is to them that you must please first. If there is no perfect density, keep in mind that if your page doesn't contain enough keywords (or if the choice of your keywords is poor), it may be able to position itself for some time but will disappear Google's first pages of results… It's all about dosage!
To parody a famous campaign to warn the French against the systematic use of antibiotics, one could say that "keywords are good. It sucks to abuse it." To find out if the pages of your site contain too many (or not enough!) keywords, you can draw your calculator and ask 'number of occurrences of the word' / 'total number of words in the page'. Some sites (optimiz.me, outiref.fr, outils-référencment.com) can also calculate the density of your keywords online. Finally, you can simply reread (or have your text reread) after you've deleted all repetitions of your keyword. If the result is incomprehensible, you will need to review your copy. And incidentally invest in a dictionary of synonyms.
For referencing a web page, Google not only takes into account the repetition of a keyword but also the presence of synonyms ("co-occurrences" in web language) and meta-words, i.e. words related to your main keyword.
Even more than their repetition, locating a keyword within the pages of your site will have a decisive impact in terms of REFERencing. By placing them judiciously (at the beginning of your text, in the title tag, in the alt attribute of your images, in the links…), you will greatly improve the effectiveness of your keywords.