What it is and how it works

What is keyword density? Can it be calculated? Is there an optimal percentage of keyword density? Is it important for website optimization? If so, how much?

If you are asking yourself these questions, you are probably seeking information about SEO and how to optimize web pages for search engines.

On this page, I will try to clarify the concept of keyword density, including:

  • What it is and how it is calculated;
  • why keyword density matters;
  • how the “keyword density” factor has evolved within Google’s algorithm;
  • what keyword stuffing is;
  • the utility of density and its optimal percentage;
  • online keyword density checker tools to check the density value.

Do you want more information about keyword density? Discover Digital Coach®’s SEO training!

keyword density example

What is Keyword Density and how it is calculated

Keyword density, or keyword frequency, represents the number of times a keyword appears in the text of a web page. It could be an exact or semantic keyword, depending on how the search engine interprets the user’s query.

Its density calculation is a simple percentage: just divide the number of times the keyword appears within the text to be analyzed by the total number of words and then multiply by 100.

The formula for calculating keyword density is:

how keyword calculated

Is Keyword Density important?

For organic ranking, keyword density is a fundamental concept. Its importance stems from its potential impact on the ranking of a website’s content on the SERP and consequently on the organic visibility of online pages.

Over the years, however, the consideration of keyword density in terms of ranking has been revised through various algorithm updates.

It is therefore useful to understand the impact of keyword density following these changes. For almost all our questions, we seek answers on the web, and the entity that responds to us is a search engine.

Globally, this category is predominantly represented by Google, which in 2019 processed about 81% of user requests worldwide (source: NetMarketShare).  Answers are returned after querying the system with specific keywords.

The results obtained are listed on the so-called SERP (Search Engine Result Page) in a specific order, starting from the most relevant to the user’s search intentions.

Google’s task is to identify and organize information by creating personalized indices for each keyword or keyphrase, based on user browsing habits and geolocation.

importance of keyword

The importance of keyword density stems from the fact that it is one of the fundamental factors in determining a web page’s relevance to the user’s query and its subsequent placement on the results page.

To understand where keyword density comes into play, one must comprehend the underlying process of result retrieval.

Since the web is constantly expanding, Google and other search engines monitor new elements by scanning pages using software that continuously and automatically analyzes network content, known as crawlers or spiders.

To determine the topic of web pages, these bots focus on certain elements such as the title tag, meta description, and alt text in images, identifying recurring keywords contained within these elements.

Once the content is understood, the bots archive the information found into an index.

When a user searches for a keyword or key phrase, Google already has the pages to display in its archive but presents them in a ranking visible on the SERP returned based on their relevance to the user’s request.

To determine relevance, Google and other search engines use an algorithm that determines the factors to consider.

In practice, no one knows the “magic recipe” contained in the ranking algorithms: while some factors and metrics are more or less known, it is more challenging to identify the correlation between them.

It goes without saying that the better the positioning in search results, the higher the visibility of the brand or published content.

For a company, this can translate, for example, into easier lead generation and contacts to convert into customers.

Search Engine Optimization (SEO) deals precisely with this: getting content to appear in the top positions of search results, partly through optimal keyword density.

Unlock your SEO potential, and challenge yourself with our test

seo specialist test

The progression of the “Keyword Density” factor in Google’s algorithm

So, keyword density has always been a fundamental element for the search engine to identify the topic of online content, its relevance to the user’s query, and the resulting ranking.

However, over time, Google’s original positioning algorithm allowed the proliferation of SEO techniques that could alter the SERP positioning.

These practices are commonly referred to as black hat techniques, from the classic representation of “bad guys” in Western movies who were always depicted wearing dark hats, in contrast to the “good guys” with white hats.

This led Google, starting in 2011, to limit these practices by releasing an update to the ranking algorithm called the Panda Update to remove low-quality sites from the SERP.

These sites were designed solely to generate traffic for commercial and positioning purposes. As Google states in the Webmaster Central Blog to better specify the evolutions brought about by Panda:

“In recent months, we’ve focused particularly on helping people find high-quality sites in Google’s search results. […]

Our site quality algorithms are aimed at helping people find “high-quality” sites by reducing the ranking of low-quality content. […]

Here are some questions that one could use to assess the “quality” of a page or an article. […]

Another specific piece of guidance we’ve offered is that low-quality content on some parts of a website can impact the whole site’s rankings.

Hence removing low-quality pages, merging or improving the content of individual shallow pages into more useful pages, or moving low-quality pages to a different domain could eventually help the rankings of your higher-quality content.”

The Panda update affected, among others, sites with excessive advertising and little content, duplicate content, slow websites, and over-optimized pages.

This is specifically created to force their ranking in SERPs through excessive use of the main keyword.

It penalized a practice that had spread among webmasters, which involved the excessive repetition of keywords within the web page text, making it unnatural to read: keyword stuffing.


Don’t miss out on top rankings! Claim your free SEO Copywriting ebook instantly

seo copywriting ebook guide

Keyword stuffing: the ambiguity of keyword density

Keyword stuffing literally means “keyword stuffing” and involves overloading web content with keywords in an attempt to force a site’s ranking in SERPs.

After Google’s Panda update, stuffing has become one of the techniques that can seriously compromise the user’s reading experience.

Also, the ultimate goal of every search engine is to respond to user queries as quickly and relevantly as possible. In short, today, an excessive keyword density could prove to be a counterproductive


Is there an optimal keyword density?

There are no clearly defined rules to identify an optimal keyword density. There are no specific studies or statistics to rely on to determine the optimal keyword density.

Even Google does not provide guidelines that specify how many keywords a web page should contain. However, following the Panda update, Google’s webmasters provided some insights on their YouTube channel.

“Using a keyword once or twice on a particular page can increase its chances of being considered for relevant rankings. However, using it seven or eight times will not have any positive effect. […]

Reflect on the keyword you want to rank for and try to integrate it into the text naturally. […] Make sure you’re using the right keyword and that the text appears natural, and you’re already on the right track.”

In summary, there is no optimal percentage. However, there are some “common sense” rules that can help achieve good rankings. It’s definitely important to avoid keyword redundancy (stuffing).

It’s crucial to place keywords in the right places, such as title tags, preferably at the beginning of the title, headings (H1, H2, H3, …), URL, meta description, ALT attributes for images, textual content, preferably in the upper part of the page or article.

Finally, it would be useful to follow these content writing tips: correctly use the long-tail theory, meaning using generic high-search keywords for ranking purposes and long-tail keywords for conversion purposes.

Do not focus on keyword repetition, prioritize user intent over density by creating pleasant and readable texts.

Choose strong headlines to increase CTR (Click Through Rate, i.e., the number of clicks in relation to the number of impressions), and create interesting content to increase the time spent on the page.


Boost your website’s rank! Your free ebook awaits! Click here to download

SEO-SEM Specialist ebook guide

Keyword Density tool online

Although keyword density is just one of over two hundred factors determining SERP ranking there is no optimal percentage.

It is good practice to use tools to check the frequency of keyword usage, also to avoid falling into stuffing. In this regard, we can find online tool checkers and keyword density generators for keyword verification.

Their operation is more or less similar and usually allows the analysis of web pages either by entering the URL, if they are already published online, or portions of text.

For example, we can mention:

  • The text analyzer by provides information on the number of characters, words, syllables, and sentences, lexical density, frequency of sentences composed of 8 words up to single words, and the calculation of the density of each processed option.
  • The keyword density checker by Small SEO Tools, allows you to specify the keywords to analyze and include meta tags, titles, and alt titles in the search. Among the results, we will obtain a tag cloud, a box containing the keywords identified by it with their respective frequency, and the list of keywords composed of one, two, three, and four words with their density.


Request more information