The optimum keyword density

Some years ago search engine optimization was mainly about using the right keyword densities in the text of your website. Nowadays it seems to have lost much of its importance. But isn’t it important anymore? In this article I will give my opinion and maybe we can get a discussion going on what you think.

What is keyword density?
Keyword density is the percentage a keyword is of the total amount of words, a specific piece of text or code, or a percentage of all the characters. Besides density, the keyword prominence is also an important factor in keyword placement. Prominence is mainly how far the keyword is from the beginning of the text or other important spots within the code.

Is there an optimum keyword density?
Yes, there probably is! But it is a different density for each search engine, each HTML tag, each keyword and the amount of words. The exact percentages change all te time. An optimum density is more a minimum and maximum density to work between, then an exact number that is perfect all the time. What the minimum and maximum percentages are depends on what numbers you use to calculate them.

Calculating keyword density
There are several methods and tools to calculate keyword densities. In my opinion the best way is to take the total amount of words between a specific region or HTML tag. The most important densities are: Percentage of total words within any tag; And percentage of total words within the body tag.

A good tool to calculate keyword density is Ranks.nl (http://www.ranks.nl/tools/spider.html). This tool gives you many options to measure and compare the numbers. The optimum range I will give later in this article are ones you measure with ranks.

What should the numbers look like?
Exact numbers aren’t very important for your ranking. Even the numbers I give here are just indications and a page that has entirely different numbers could rank just as well. The closer the numbers are the better, but in the entire algorithm it is just a small factor.

• The total number of words shouldn’t be too high or too low. Optimum amount for the percentages I give below is between 300 and 600 words. Use as little code besides text on your page because it could all dilute the importance of the main keyword.
• The main keyword should always be represented in the page title (title tag). Other important places are: URL, headers (h1), linktext, bold text, italic text and alt tags. Within these tags the main keyword can and should have a very high percentage.
• The main keyword should have a higher percentage than other words. It is not the percentage that counts, but the focus on the keyword compared to other words. In my opinion this is the main ingredient of good page optimization.
• A percentage higher than 3% and below 10% of the total wordcount is best, but I often keep it below 5%. All unimportant words should be kept under 3%. Avoiding unimportant repeats is more important than repeating the main keyword.
• Stems are the basic words that keywords are made of. A keyword can contain multiple stems. All the keywords posting, poster, posted, postmodern all contain the stem “post”. Keywords or stems that are included in other words are counted in the algorithms of some search engines. Keep keyword repeats including stem repeats below a certain spam threshold.
• If you repeat keywords too often, use synonyms so the theme of the page is still strong. The theme of the page is almost as important as the keyword itself. Some search engines are good at theme destillation (guessing what a text is about) and some don’t do it at all. In the future it will become more and more important.
• The “one page, one keyword” strategy works best, but for words with little competition you can always combine multiple keywords in one page.

My opinion:
Focus is everything! Focus on keyword related text and prevent unintentional focus on another topic. Focussing is done in repeats and accentuated code parts (title, bold, etc.).
The theme of pages (internal and external) linking to a page is more important than having perfect densities. So focus on theme on a wide scale and focus on keyword on a page scale and in linktext.

Please comment because this topic is something opinions vary widely on. How important do you think keyword density is?

Friday, December 29th, 2006 at 9:22 pm | Opinions, Algorithms
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