What Is Keyword Density?

Keyword density is simply taking a mathematical view of your page content. It is defined as the percentage of keywords or keyword phrases that appear in the total page content. To discover it, you perform (or use a tool that performs) a simple match problem:

Keywords ÷ Total Words = Keyword Density

So in an advertising blurb or article with 300 words of which 10 were keywords, the keyword density would be 3.3%. If you figure this yourself on a calculator, remember that an easy switch from a decimal to a percentage is to multiple the answer by 100.

Help for Figuring Keyword Density

There are many folks who think that keyword density is one of the top factors in search engine optimization, and consequently there are a number of free services to help you figure keyword density. Some have you enter a text block, while others work from a URL. Some ask whether to include Meta Tag Keywords, and some allow you to analyze multiple keywords in one page or text block. A search on “free keyword density counter” will provide you with a range of options.

But What Exactly Is a Keyword?

That depends on who you ask. The standard definition is that a keyword is a word or short phrase that people search for, and its repetition is used as an index of the focus of content. Google, for example, sticks to this definition. But, Google is not the only search engine in town. Yahoo! in particular includes both synonyms and inflected forms (plurals, adjectival forms and the verb –ing and –ed endings, etc.) in its keyword count. For example, in the following text:

If you like to read books during your summer vacation, but don’t want to buy them, come visit the library! Reading can be done in a comfortable chair on our air-conditioned premises, or all manner of readable material can be checked out and enjoyed in the comfort of your own home, at the beach, or poolside. Besides improving your mind, perusing the latest best seller can give you some great conversation starters.

If the keyword is read, Google will count one instance—the fifth word in the first sentence. Yahoo! will count read, reading, readable, and the synonymperusing: four times as many words in the same passage.

So if you’re optimizing for Yahoo!, keep this in mind, and especially take note when choosing a keyword density counter to make sure its taking these elements into account.

More About Keywords

Many articles talk about keyword density as if it were the be-all and end-all of SEO work, and this is simply not the case, even within the realm of talking about keywords. Keyword density is actually only one of the attributes of keywords that should figure into your thinking. Two others are keyword prominence and keyword proximity.

Keyword prominence refers to how obvious the keywords are. This boils down to both how close to the top of the page they appear in text as well as their use in title tags and heads, not to mention the domain name itself. Keyword proximity refers to how close together the keywords appear. A webpage selling a highly unusual, rare, and sought after product that people will be over the moon to find might get away with:

Giraffes! Giraffes! Giraffes!

You’ll be astounded at our array of African wildlife, all happy and healthy and ready to join you in your extensive grounds for a lifetime of enjoyable interaction. Call us now for a free DVD extolling the wonders of owning your own authentic animals from another continent.

It’s true that overall it only has a 6% keyword density and that the keywords are prominent.  But most of the time, it’s far better to space the keywords out through the text or page copy. Besides these commonsense observations, its important to be aware of the fact that repeating keywords multiple times in a row—in title tags or text—has been pointed to as a spam signal, so immediate repetition is something to approach cautiously, even in situations in which it might seem entirely justified.

What’s a Good Keyword Density?

There are varying schools of thought about what keyword density to strive for, with some suggesting that about 2–4% is the optimum percentage—a signal of relevance without falling into the realm of spam. Others say 3–7%. Some give figures as high as 12%. In any case, pretty much every white hat believes that this is not simply a case of “more is better”: too many keywords at some point crosses over into keyword stuffing, which is something to avoid as it may provoke a negative reaction from both search engines and your visitors. Specifically, Yahoo! and MSN Search (which along with Google form the “big three” of the search engines) “prefer” a higher keyword density. Remember that given the way that Yahoo! defines a keyword, it’s likely to find a higher count in any case.

But there is another school of thought among professional SEOs that downplays the importance of keywords considerably. These folks might be characterized as considering keyword density to be properly used as a test for outliers—the times when you’ve used way too many or too few keywords without realizing it. They also tend to agree that writing to keyword density has a tendency to produce poor quality writing because writers are influenced to write unnaturally and generically as if every context were the same, without consideration for the word density that would normally fit the particular situation.

And it is this second view that is supported by Google, which takes a different approach to keyword density, one that emphasizes “organic” content. For example, Vanessa Fox, Product Manager of Google Webmaster Central, writing in the Official Google Webmaster Central Blog not only suggests that webmasters focus on visitors rather than search engines; she explicitly says, “Visitor-friendly design makes for search engine friendly design as well” and goes on to say, “Don’t try to cram as many words in as possible. . . .”

So the best answer to the best keyword density is definitely, “It depends.”