Keywords are an important part of your SEO strategy.
Together with relevant content and an optimized website design, ranking for the right keywords will help make your website stand out from the crowd – and get closer to the top of search engine results pages (SERPs).
So it’s no wonder that a significant amount of SEO advice has been focused on keywords: research can help you select and rank keywords with the best performing in your market, which in turn increases user engagement and increases overall sales.
But how many keywords are enough? How many are too many How do you know? And what if Google and other search engines find that your website is “crammed” with keywords?
In our Beginner’s Guide to Keyword Density, we’ll cover the basics, examine why it matters, and provide functional formulas and simple tools to help ensure your keyword strategies are working as intended.
What is keyword density?
Keyword density – also known as keyword frequency – describes the frequency with which a particular keyword is displayed on a web page compared to the total number of words.
It is often given as a percentage or a ratio. The higher the value, the more your selected keyword will appear on your page.
Why Keyword Density Matters
Keywords drive search. When users search for products or services, they usually use a keyword that reflects their general intent and expect search engines to produce relevant results.
While tools like Google now take into account factors like geographic area and page authority, defined in part by the number of visitors to your website and in part by “dofollow” links from reputable websites that point to your page, keywords remain more crucial Importance factor for the success of a website.
The restriction? You can’t just “paste” as many keywords into your content as you can and expect reliable results.
During the wild west days of the first search engines, brands and SEO firms were writing low value content and populating it with keywords and keyword tags, as well as links to similarly populated pages on the same website. Unsurprisingly, visitors became frustrated and search engine providers realized they needed a better approach.
Now keyword stuffing has the opposite effect: Search engines penalize the page rankings of websites that still choose keyword stuff.
By Numbers: The Keyword Density Formula
How do you calculate keyword density? The formula is simple: divide the number of times a keyword is used on your page by the total number of words on the page.
Here’s a simple example: Your page has 1,000 words and your keyword is used ten times. Which gives:
10/1000 = 0.001
Multiply that by 100 to get a percentage, which in this case is 1%.
There is also another formula that is sometimes used to evaluate keyword usage: TF-IDF, which stands for “term frequency-inverse document frequency”. The aim here is to evaluate the frequency of a keyword on certain pages (TF) based on the frequency with which that word appears on several pages of your website (IDF). The result will help determine how relevant your keyword is to certain pages.
While TF is straightforward, it’s easy to get distracted by IDF. The goal here is to understand the rarity of your keyword in multiple documents. IDF is measured in values between 0 and 1. The closer to 0, the more a word will appear on your pages. The closer to 1, the more it appears on a single page and not on any other.
This is the “opposite” nature of the calculation: lower values mean more keyword usage.
See this formula in practice. Applied to very common words like “that” or “but”, the TD-IDF value approaches zero. Applied to a specific keyword, the value should be much closer to 1. Otherwise, you may need to rethink your keyword strategy.
Understanding the optimal keyword density
There are no fixed rules for keyword density that go beyond the always relevant advice “no keywords”. However, many SEOs recommend using around one keyword per 200 words.
Your content may score similarly by a little more or a little less, but it is widely believed that Google and other search engines respond well to the keyword density of around 0.5%.
Also, think about the value of keyword variations – words and phrases that are similar but not identical to your primary keyword. For example, let’s say your website sells outdoor lighting solutions. While your keyword is “Outdoor Lighting” with the highest score on SERPs, including as many uses of that keyword in as many pages as possible will reduce rather than improve overall SEO.
Instead, consider keyword variations. Terms that are close to your primary keyword but are not an exact copy. In the case of “outdoor lighting”, variations such as “garden lighting”, “patio lighting”, “deck lighting”, or “landscape lighting” can help your page rank higher without breaking the keyword-filling rules.
Not sure which variants make the most sense for your website? Use the “Search Queries Related” section at the bottom of Google SERP for your primary keyword. Here’s why: Google put a lot of time and effort into understanding the intent so that the “Search related to” section comes up with terms similar to your primary keyword.
Keyword density tools
While you can calculate keyword density yourself by counting the total number of words and keywords on each page of your website. However, this can quickly become time and resource consuming as your website expands and the volume of pages increases.
Keyword density tools help streamline this process. Possible options are:
1. SEO Review Tools Keyword Density Checker
This free tool is browser-based. Simply enter your website url or page text and run the I’m not a robot captcha to perform a keyword density check. While this tool doesn’t provide a detailed analysis of other options in the list, it is a great way to get an idea of the current keyword density.
2. SEOBook Keyword Density Analyzer
Similar to the tool above, the SEOBook Keyword Density Analyzer is free – but an account is required to use it. In addition to basic keyword density reports, this tool also lets you search Google for your target keyword, get data for five of the top rated pages with the same keyword, and then analyze them to see how your keyword stacks up.
3. WordPress SEO Post Optimizer
If you prefer a WordPress plugin for evaluating keyword density, then you should consider the WordPress SEO Post Optimizer. This tool costs $ 19, but it does check a variety of SEO conditions, including keyword density, to make sure your content has a high ranking with the SERPs.
4. WPMUDEV SmartCrawl
Another WordPress pluging, WPMUDEV SmartCrawl, is free for seven days and then costs $ 5 per month. In addition to assessing keyword density, the tool includes automated SEO reviews and reports, title and metadata ratings, and detailed website crawls, scans, and reports.
Keys (words) to the kingdom
Do you want to improve your SERP position and increase the impact on the website? Start with strong keywords.
The restriction? Keyword balance is the key to search success. By measuring and regularly evaluating the keyword density of both pages and your website, you can increase the relevant SEO impact and avoid the ranking pitfalls of an overly dense keyword distribution.