Keyword difficulty explained: A practical guide to smarter SEO

Ever wonder why some articles shoot to the top of Google while others just disappear? A lot of the time, it comes down to one thing: keyword difficulty.

If you aim for keywords that are way too competitive, you're just setting yourself up for a lot of work with no reward. But if you only go after keywords with zero competition, you might not get much traffic. The trick is finding that sweet spot between what people are searching for and what you can actually rank for.

This guide will break down what keyword difficulty really is, how different SEO tools measure it, and how you can use it to build a smarter content plan. We'll skip the fluff and give you a practical way to make better content decisions that save you time and bring in traffic.

We'll also touch on how tools like the eesel AI blog writer can help you go from just staring at numbers to creating great content that can compete for the keywords you care about. It's the same method we used to take our own blog from 700 to 750,000 daily impressions in only three months.

How SEO tools define keyword difficulty

Okay, let's start with the basics. Keyword difficulty (KD), or SEO difficulty, is a metric that tries to guess how hard it'll be to get on the first page of Google for a certain keyword. You can think of it like a weather report for your content: is it a light breeze or a category 5 hurricane?

Most SEO tools show this on a 0-100 scale. Zero is a piece of cake, and 100 is like trying to take on Wikipedia. But here's the thing: those numbers can mean very different things depending on which tool you're using.

For instance, Semrush breaks its scale into six levels. A score of 0-14 is "Very easy," suggesting a new page could rank without much fuss. A score of 50-69, though, is "Difficult" and means you'll need amazing content and a good backlink strategy. Ahrefs is more to the point. Its KD score is tied to the number of referring domains (links from other websites) you'll likely need to get into the top 10. A keyword with a KD of 40 means you'll probably need about 56 different websites linking to your page to stand a chance.

It's really important to remember that keyword difficulty is not a Google metric. It's a calculation made by SEO software companies to help people like us figure out where to focus.

unless you have knowledge of the internal workings of these scores from ahrefs and SEMrush, who is to say 20 KD in ahrefs isn't exactly the same as 50 KD in SEMrush? There are different ways to scale a score from 0 to 100.

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Why keyword difficulty is a crucial SEO metric

Keyword difficulty is more than just a score; it’s a compass for your content strategy. Understanding it helps you in a few big ways.

It helps you manage your resources better. It keeps you from spending weeks creating a masterpiece for a keyword you have virtually no shot at ranking for, especially if your site is new. It's all about working smarter.

It also lets you build a strategy based on data. Instead of just guessing, you can pick keywords that give you the best mix of search volume and rankability. This means a better return on the time you put into content.

You can also set realistic expectations. Knowing a keyword's difficulty helps you estimate how long it might take to see results and what it will take to get there (like building links).

an easy kd just means you can really take first in search results in less than 2 weeks in some cases that I’ve seen

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Finally, it helps you find strategic gaps. Sometimes you'll stumble upon a keyword with high search volume but low difficulty. These are the goldmines that can drive a lot of traffic and give your growth a real boost.

The core factors behind keyword difficulty

So, how do these SEO tools calculate this number? They look at the pages that are already ranking at the top (usually the first 10 on Google) and figure out what they have in common. Their exact formulas are kept under wraps, but they generally focus on a few key things.

The power of backlinks and website authority

At the end of the day, keyword difficulty is mostly about authority.

Backlinks (links from other websites to yours) are basically votes of confidence for Google. The more high-quality "votes" a page gets, the more authority it appears to have. Both Ahrefs and Semrush say that the number and quality of backlinks are a huge part of their KD calculations.

SEO tools look at two kinds of authority: the overall strength of the website (called Domain Rating or Authority Score) and the strength of the specific page that's ranking. A page on a big-name site like The New York Times has a huge advantage. That said, a really well-made, detailed page can sometimes beat out a weaker page, even if it's on a site with more authority.

Content quality and search intent alignment

A high KD score doesn't automatically mean a keyword is off-limits. You just have to look for weaknesses in the current top results. The team at Ahrefs recommends checking for these "cracks." If the #1 ranking content is outdated, flimsy, or doesn't answer the user's question (which means it's a poor match for search intent), then you've found your opening.

Google watches how people interact with search results. If a user clicks the first link, hits the back button right away, and then clicks the tenth link (and actually stays there), that tells Google the tenth result is probably better. You want to be that better result.

The impact of SERP features

The Google search results page isn't just ten blue links these days. It's packed with things like Featured Snippets, AI Overviews, "People Also Ask" boxes, shopping ads, and image carousels. All this stuff can push the regular organic results way down the page.

When these features are present, a keyword becomes more competitive, not just for ranking but for actually getting clicks. You could be the #1 organic result, but if you're sitting below an AI Overview, a video carousel, and a bunch of ads, your click-through rate is going to take a hit. Semrush gets this, which is why its KD formula includes the presence of 11 different SERP features, from "Instant answer" to "Local pack."

How Ahrefs and Semrush handle keyword difficulty

It's worth saying again: a KD score of "50" in Ahrefs is not the same as a "50" in Semrush. They use different ingredients to come up with their scores, so let's see what's in the mix.

Ahrefs: A backlink-centric approach

Ahrefs is known for keeping things simple. It calculates its KD score almost entirely based on the number of referring domains linking to the top 10 pages for a keyword.

The good part? It's simple, clear, and gives you a concrete goal. To rank, you'll likely need a similar number of quality backlinks as the pages already at the top. The downside? It's a little one-dimensional. It doesn't focus as much on other key factors like content quality or on-page SEO. That's why even Ahrefs tells you to manually check the search results instead of just relying on the number.

Semrush: A multi-factor analysis

Semrush looks at the bigger picture, analyzing over a dozen different factors. Their own docs say their formula is a weighted average that includes the median number of referring domains (41.22% weight), the median Authority Score of the ranking sites (16.99% weight), search volume (9.47% weight), and whether certain SERP features are present.

The good part? It gives you a more balanced view of the competition, which can often feel more on the mark. The downside? The formula is a bit of a mystery. It can be tough to pinpoint exactly what's driving a score up or down without doing more digging.

A note on personal keyword difficulty (PKD)

Both tools get that difficulty isn't one-size-fits-all. What's tough for a new blog could be a walk in the park for a big, established site. That's why Semrush has a "Personal Keyword Difficulty" score. It adjusts the difficulty based on your own website's authority and relevance to the topic, using an AI algorithm. Ahrefs is on board with this idea too and even provides a Claude prompt to help you figure out your own PKD by considering your Domain Rating and how well the keyword aligns with your content.

A smarter approach to keywords with the eesel AI blog writer

Checking keyword difficulty is a great first step, but it's only half the job. The other half is creating content that can actually compete. This is where many marketing teams hit a wall, burning days on research, writing, and formatting.

The eesel AI blog writer turns this process around. Instead of just handing you data and saying "good luck," it takes your target keyword and builds a complete, SEO-optimized blog post that's ready to go.

Here’s a peek at how it works. First, it does context-aware content creation. When you plug in a keyword, eesel AI doesn't just spit out text. It researches the topic to understand search intent and checks out the top-ranking articles. If you need a comparison post, it finds pricing data. For a product review, it digs up tech specs. This makes sure your content hits the mark.

It also handles automatic asset generation. A big part of beating the competition is making your page more valuable. eesel AI automatically adds things like AI-generated images, infographics, comparison tables, and relevant YouTube videos to keep readers engaged.

Finally, it adds authentic social proof. To get that human touch that a lot of AI content misses, the tool pulls in real quotes from Reddit and other forums. This makes your content feel more credible and real.

This is exactly how we grew our blog impressions at eesel from 700 to 750,000 per day in just three months. We focused on creating better content for keywords we could actually rank for, which helped us build authority and get traffic way faster than doing it all by hand.

How to use keyword difficulty in your content strategy

So, how do you actually use this stuff?

If you have a new website, go for the low-hanging fruit. Target keywords with a difficulty score in the "Very easy" or "Easy" range (like under 30 in Semrush). These are usually long-tail keywords, which are phrases with three or more words. They get less search traffic, but they also have way less competition. Winning these early on helps you build authority and get some momentum.

If you have an established website, you can mix it up. Your site's authority lets you target a blend of low, medium, and even some high-difficulty keywords. You can go after valuable "head" terms while still using long-tail keywords to pull in more specific traffic.

For a deeper dive into what keyword difficulty means and how to apply it, this video offers a clear and easy-to-understand explanation that complements the strategies discussed here.

A video where keyword difficulty explained in an easy-to-understand way for content creators and SEOs.

Keyword difficulty: Your guide, not a gatekeeper

At the end of the day, keyword difficulty isn't a rule that says "you can't rank for this." It's more of a guide that helps you answer a better question: "Is this keyword worth my time right now?"

By understanding what goes into the difficulty score and using it to plan your content, you can save a ton of time and focus on creating articles that will actually make a difference. It's all about finding that sweet spot where what your audience is searching for meets what you can realistically rank for.

Stop guessing and start creating. Generate your first SEO-optimized blog post for free with the eesel AI blog writer and see for yourself how easy it is to turn keyword research into content that ranks.