How Many Keywords Should I Use for SEO?

Throughout several blog posts, I’ve reiterated that keyword stuffing is black-hat SEO. This refers to filling the content with as many SEO keywords as possible to rank high in search results. But as I’ll discuss in detail in a little while, under no circumstances should anyone – SEO professional or not – use this for search engine optimization.

If that’s the case, then how many is too many? The truth is that there’s no clear answer, but it doesn’t mean we won’t try to find the sweet spot.

Why Too Many Keywords Are Bad

In the years leading to the great Panda and Penguin shake-ups of the early 2010s, it wasn’t unusual for content to contain an unhealthy amount of keywords. Look at the image taken from a web page on the deep Web below. “Pet sitting” was mentioned so many times that I wouldn’t blame you if you never wanted to come across the term again.

But back then, such practices were your best bet in ranking on search results. Algorithms at the time were far less sophisticated than the ones we have now, mainly based on how many times the content mentioned the keyword. Even with the introduction of advanced algorithms like PageRank, keyword stuffing remained a common practice.

Over time, search engines – especially Google – found the practice inconvenient to users. Let’s go back to the example above. It’s supposed to talk about things to remember when looking for a pet sitter in Australia. But after going through it, all I got was:

• Reliably available in the hours you need them
• Special services like medication and special care needs
• Availability of resources and well-trained staff

The rest of the content consists of mentions of different keywords that make little sense and ideas that have been mentioned once too many times. There’s nothing redeemable about this piece, and keyword stuffing is mainly to blame.

Google led a concerted effort to dilute the practice’s effectiveness and discourage sites from doing it. The most prominent was the Panda update, which targeted content farms: sites that mass-produce low-effort content. It later published a set of guide questions for webmasters to determine the quality of their content.

That’s why examples like this lie dormant in the deep Web. Such content was only made to grow its parent site’s backlink profile with low-quality links, which is another black-hat SEO practice. Despite Google’s efforts, many sites still stuff their content with keywords.

What’s the Magic Number?

Unfortunately, keyword density – the number of keywords proportional to the content’s total word count – isn’t one aspect of SEO that Google has made publicly available. And the company isn’t about to reveal its algorithm fully anytime soon.

As such, we can only rely on Google’s few official statements and educated guesswork. Here are some rules of thumb I’ve read about keyword density.

The 1-2% Rule

The most common of these rules is what I call the 1-2% Rule, which states that keywords shouldn’t comprise more than 2% of the content’s word count. If a product or service page has 1,000 words, keywords should be less than 20.

However, the drawback of this rule is already evident here. We have little to no idea how much search engines will tolerate before they decide to flag the content for keyword spam. Twenty keywords can appear too many, especially if there’s only a specific keyword to rank for, and expect that number to increase with the word count.

This rule also risks reducing the number of words you can otherwise allocate to explaining the main topic in depth, especially with long-tail keywords. Imagine populating a seven or eight-word-long keyword tens of times, some of which don’t add value to the reader.

The Goldilocks Number

I stumbled upon this one from a blog post by a prominent digital marketing firm. Referred to as the “Goldilocks Number,” this rule of thumb accounts for the number of pages you want to rank in search results. It’s a bit of a shorthand, but the steps are as follows:

• Assume that one page can only have one to four keywords
• Multiply the keyword count range by the number of pages to rank
• Multiply the number of pages by 2.5 to get the Goldilocks Number

Let’s set the scene. I want to improve the search enginew rankings of my Melbourne hub homepage and its three service pages. After doing keyword research, I found around seven good keywords to use for SEO. Doing the math, the ideal range is between 7 and 28 keywords, and the sweet spot plays around ten keywords.

Compared to the 1-2% Rule, this one results in more workable numbers and a lower risk of penalties thanks to the one-to-four keyword range. However, this becomes unwieldly when you have dozens of pages to optimise. If your site is several years old and has blog posts dating back to your brand’s founding, the keyword count can easily exceed the ideal range.

The One-Keyword Rule

This rule of thumb is pretty self-explanatory. Only target one keyword per page, period.

The idea behind this rule revolves around keyword dilution, a phenomenon where the main keyword loses its power to other non-relevant keywords on a single page. Despite search engine algorithms growing more sophisticated, they’re still prone to red herrings. Placing a keyword that doesn’t complement the main keyword will make the search engine struggle to learn what the site content is really about.

At least, that’s what some site owners think.

If this Google help page is any indication, keyword dilution isn’t all that common. Google’s development team is aware that sites rank for many keywords, so they designed the search engine algorithm to be more accurate in deciphering relevance. If some dilution happens, it’s less likely to be as serious as some site owners perceive.

Another downside is that your site can lose to other sites ranking for many keywords. SEO is about covering as many bases as possible, including relevant search terms. Why rank for one term when you know plenty of others can be just as beneficial?

One Primary, Several Secondary

As long as we base our ideas mostly on speculation, we can’t get a concrete answer. But based on what we’ve discussed, I suggest Ahrefs’ approach of using one primary keyword and a handful of secondary keywords.

This approach works because it gives you an idea for a content topic and the subtopics to go with it. Spread them evenly across the quality content, with the primary keyword at the H1 tag and the rest on other subheads and paragraphs. Remember to exercise some restraint to avoid getting flagged for keyword stuffing.