SEO, Thought Leaders

How to Implement TF-IDF Into Your Keyword Strategy

May 14, 2020

by Paul Teitelman

Professional SEO Expert

TF-IDF, or term frequency-inverse document frequency, is an evergreen SEO strategy that businesses can use to update old content and drive traffic.

Many companies that have tried to start a blog in the last few years or so may not be seeing the returns that their peers did only a short time before. 

There are a few potential reasons for this:

  • Low-quality content
  • Weak link profiles
  • Overly-competitive topics

One common issue that could hamper your content’s ranking is improper keyword targeting. 

In some cases, you may be able to refurbish older, low-performing content into something stronger by revisiting your keyword strategy. In this case, TF-IDF could be the secret element you’re missing.

TF-IDF is not just another “SEO hack” that tends to disappear as soon as Google puts out another algorithm. 

TF-IDF, or term frequency-inverse document frequency,  is a true SEO strategy and resource, making it an evergreen option for content marketers.

This article shows how to implement this algorithm into your keyword strategy.

How to Use TF-IDF In Your Keyword Strategy

  1. Perform conventional keyword research
  2. Look for related keywords
  3. Find multi-word phrases
  4. Look for similar backlinks
  5. Avoid common pitfalls

What Is TF-IDF?

The term TF-IDF represents a complicated algorithm designed to show not just the frequency, but the importance of all words in the body of a given document. 

TF-IDF Equation: IDF=log(1+total documents/documents with keyword)


This example from Link Assistant shows the original algorithm, but we’ll show a less complicated way to integrate this into your work.

TF-IDF can make a huge difference from an SEO perspective. Chances are that you’ve already done proper keyword research for your content, figuring out what your target audience is searching for and the topics that you can build around those queries. But what about the rest of the words in your content? TF-IDF helps you figure out the words and phrases outside of your keywords that you need to rank in Google.

Let’s say you were writing an article titled “How to Plan a Cheap Summer Vacation.” Terms such as “vacation,” “summer,” and “budget” seem like pretty safe bets, right? Phrases like “summer vacations for cheap” and “inexpensive vacations near me” are good for long-tail keywords as well. 

TF-IDF, however, may show you that high-ranking blogs and articles for these keywords also use words such as “hotels,” “airfare,” or “families.” Adding these related keywords could help your content rank.

Step 1: Perform Conventional Keyword Research

TF-IDF still involves conventional keyword research. 

Basic keyword research involves looking at potential keywords in your SEO tool platform of choice to see how competitive those keywords are and learn more about related keywords that could be useful.

Ahrefs, for example, shows the number of people searching for keywords and related terms in a convenient list format.

ahrefs phrase match keyword tool


Keyword density shows the level of competition you can expect from targeting different keywords. Ahrefs also allows you to filter by the number of words in a keyword to find long or short keywords.

If you don’t have an Ahrefs account, you can also use other SEO tools such as Moz or Google Ads to learn about high-value keywords.

Step 2: Look for Related Keywords

Once you’ve completed your regular keyword research, start looking for related keywords that your competitors might be ranking for. 

There are several SEO tools you can use for TF-IDF, so feel free to experiment until you find one you like. The main feature you need is the ability to see what the top-performing blogs about your chosen keywords from step 1 are using. 

Using our example from before, “summer vacations for cheap,” vacations, will obviously be one of those words. However, you may also see something like “attractions.” 

What this means for you as a content creator is that a section about cheap attractions is key for this topic. If you didn’t cover it, now you know you should. 

Without words like these, Google considers your content lower-quality, and your content won’t rank as high.

Step 3: Find Multi-Word Phrases 

You should also identify multi-word phrases commonly used in high-ranking content for your chosen keyword. Those multi-word phrases can inform your content.

You don’t necessarily need to optimize for phrases as keywords, just make sure that they are being addressed somewhere in your content.

To use our earlier example of “cheap summer vacation,” a multi-word phrase associated with this topic could be “cheap flight tracker,” a topic that might be useful for readers  

Step 4: Look for Similar Backlinks 

If possible, you also want to see if these top-ranked blogs you’re researching share a lot of the same backlinks

This won’t directly affect your keyword or content selection, but it will give you an idea of what you will need to compete against to rank at the highest level. 

Step 5: Avoid Common Pitfalls

By using TF-IDF in your content strategy, you can learn the topics that people really want to see when it comes to content in your niche.

It’s possible, however, to go too far with them. For example, if you see a certain word has a high density, don’t feel that you need to imitate it.

Trying to shoehorn words to fit a specific number only leads to poor, stilted content, and that will do more to damage your content than the density will do to grow it.

Instead, you want to take TF-IDF into account in your outlining. Using our earlier example, if you were writing about cheap vacations and didn’t have a section dedicated to inexpensive family attractions, you may want to include that in your content now. 

That should organically give you the density for certain words to help rank. Remember that keyword stuffing is something that went extinct a long time ago in the SEO world. Don’t fall back into old habits. 

Incorporate TF-IDF Into Your Strategy

TF-IDF fits neatly right between the conventional keyword planning stage and the actual content creation stage. 

After you do your basic keyword research you’ll create an outline for your new content. Now’s the time to do TF-IDF research to look for potential topics you may have missed that will be relevant to your SEO campaign.

Just remember, the purpose of this isn’t to get hung up on the numbers you see in your TF-IDF tools. Instead, you want to use this information to put yourself in the mind of your target audience and make sure the topics that matter most to them are addressed. 

Use TF-IDF to add new life to underperforming content. 

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