Keyword density is a term to describe how frequently a keyword is used on a page, and is hugely important for the success of your SEO campaign.
If you miss your Keyword Density on the low end (under optimizing), you'll have trouble ranking. If you overshoot Keyword Density on the high end (over optimizing) - you risk getting your URL/site actively penalized by Google and disappearing from the SERPs entirely. Don't mess this up.
Look at this equation — it should help you understand the concept.
Keyword density = # of times keyword used ÷ total no. of words on webpage x 100
If I wrote a 100 word blog post and used a particular keyword twice, the keyword density would be 2%.
It's also important to note that a keyword can be one word, or many in a "phrase."
A keyword that is 10 words long, used 5 times in a 100 word article, is still 5% keyword density.
Why is keyword density important for SEO? The simple answer...
Keyword Density is a large factor in helping Google determine what a page is about. A fundamental aspect of the algorithm - if a page talks about the same thing over and over on a page it stands to reason that page is probably centered around that topic.
Keywords are a fundamental aspect of SEO — always have been, always will be. They are your chance to tell search engines (like Google) exactly what your webpage is about.
How many times you use your keywords (keyword density) can give Google even more hints and clues.
Pre 2011, SEOs realized this fact and began to stuff a keyword onto a page as many times as possible, so when Googlebot would come to your page about "auto insurance" and read that term was on the page 1,000 times it would think "hmm...this must be SUPER relevant to auto insurance, let's rank them highly".
This is called "keyword stuffing".
Google caught on, and introduced "Panda" - a huge change to their algorithm that began to categorize these keyword stuffed / low quality, "spammy" websites/webpages that prioritized keywords over content quality.
"Hummingbird" places greater emphasis on natural language queries, considering context and meaning over individual keywords.
Over time, search engines have become more and more "semantic" or logic-driven. An unnaturally high keyword density (keyword stuffing) once a viable SEO strategy, is now blackhat (illegal.)
This is true for all search engines (not just Google.)
Before those big Google updates, it was common to see high-ranking content with keyword densities as high as 50%.
That's definitely not going to fly today.
You want to aim for a keyword density of 1-3% to start, but like all things in SEO this can vary from keyword to keywords, and certainly from industry to industry.
That's a rate of 1-3 keywords per 100 words.
However, if you want to take a more advanced (and frankly better approach) you will want to analyze the top ranking URLs for any given keyword and see what their average keyword density is. Then, sculpt yours to fit in somewhere in the middle. Blend in. Always blend.
Popular WordPress SEO plugin Yoast recommends 0.5% to 3%.
RankMath (another plugin) says 1% to 2.5%.
The Wikipedia article on keyword density suggests 1-3%.
The key really, is to not focus on keyword density. You should be prioritizing writing useful content that helps your readers.
If you do this, naturally your keyword density will fall between 1-3%.
Long-tail keywords are obviously going to be used less than short-tail keywords.
How often do you think you can use "how to create a wordpress website" compared to "wordpress website."
Again, the key is naturally flowing.
Takeaway: A 1-3% keyword density is an optimal baseline, but the KEY is to blend in.
These days, it's not really how many times you use keywords, but where you put them.
There are a number of critical places you must have keywords featured.
The page title — also known as title tags — is the most important place to have a keyword.
In case you didn't know, the page title is the title of your webpage on SERPs (search engine results pages.)
It's what tells search engine users exactly what your webpage is about — just like a headline of an article.
Google (and other search engines) will look at the title tags and see if you have a keyword here. Make sure you do so, and front-loaded if possible.
You'll also want to put a keyword within your h1 header — this is your actual page headline.
The h1 header is often confused with the page title — it's important to know the difference.
The page title is the headline for your webpage on the SERP.
The h1 header is an HTML element on your webpage designated by an HTML tag <h1>, that basically tells Google "hey, this is the primary topic of this article".
Remember back to highschool when you were writing an outline to an essay. You have the Title of your essay (page title), and the main topic I. Main Topic Here (that's kind of like the h1).
h1 = Heading 1. A primary heading/topic to tell your readers (and search engines) what the page is talking about.
You should feature keyword variations throughout subheadings — H2, H3, etc.
Why? Well, if these "headings" are the primary topics and subtopics of an article or web page, wouldn't you want to specifically tell Google (using HTML) that "hey, this page is really about XYZ".
This article is a great example of this.
A good meta description can increase click-through rates, indirectly impacting SEO.
The meta description acts as a blurb, or preview of sorts. It lets search engine users know what your webpage is about.
If you're accurately describing your webpage, you'll most likely use a keyword.
Although many SEOs will say that the meta description does not directly influence SEO, if you look closely you will notice that when you search something on Google, the search engine will bold those keywords inside meta descriptions.... think about that for a second.
Google (and other search engines) don't see images visually — only the HTML.
For this reason, you'll want to throw a keyword in at least one image alt-text.
That being said ... technology is getting much better everyday with image recognition.
You'll want to do the same with your image filenames.
Putting a relevant keyword in your URL slug is good practice.
URLs pack a punch when it comes to SEO. In fact, it's one of the top on page seo factors.
Remember to keep it short.
Takeaway: Put keyword variations in your page title, h1 header, h2/h3 subheader, meta description, image alt-text, image filename and URL slug. Keep it varied, keep it natural.
Modern keyword strategy is less about using the same keywords frequently, but using different variations of your keyword, and supporting topics that make an article comprehensive.
These keyword variations are known as LSI keywords.
LSI (latent semantic indexing) keywords are words or phrases that are semantically similar, or highly correlated to your main keywords.
Search engines (such as Google) are intelligent — they look for these related LSI keywords.
This gives them a better understanding, a better idea of what your webpage is about.
Google even states so in this 2016 research paper.
It's also important to note that LSI keywords are not synonyms.
Synonyms — words that have similar or same meaning.
LSI Keywords — words or phrases that are related to your keyword/keywords in search engines.
Think of these like topics that you would have to discuss in order to answer someones question on a particular topic. For example, you can't really have a beginners guide to camping without discussing things like food, tents, bears & how to make a fire - even though none of those use the words "camping".
Sometimes, synonyms and LSIs are the same. If a synonym is not relevant in search engines, it is not a LSI keyword.
There are many strategies you can use to find LSI keywords.
The easiest way is to use the Google "autocomplete" feature.
The words suggested — these are LSI keywords.
Another strategy you can use is LSIKeywords.com.
Simply type your keywords into the tool — a list of LSI keywords will appear.
Let's bump the brakes here for a second... why are we talking about LSI Keywords? Did we just get off topic? No.
The reason is that LSI keywords, keyword variations, synonyms, etc. is what you should be using to help with your keyword density.
If you have a page you want to rank for "los angeles orthodontist" you shouldn't just plaster that phrase all over the page - you need to dance around it a bit.
Takeaway: Use LSI keyword variations to make your keyword SEO more semantic, and dilute your keyword density a bit.
In this post we covered keyword density as a concept, its history and its current state in the SEO world.
Keyword density refers to how many times keywords are using throughout a page, and is just a ratio to show you how often it appears.
These days it's important to keep keyword density in mind so you don't under-optimize or over-optimize - but more importantly is strategically placing keywords throughout your pages for maximum SEO impact, and building semantic relevance by covering topics succinctly and completely.
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