The 9 Best Keyword Research Tools

Keyword research is a three-step process:

1. Find keyword ideas that people are searching for
2. Check their ranking difficulty
3. Figure out the best way to rank

In this post, you’ll learn how to do these tasks with nine free keyword research tools.

The best free keyword research tools

Keyword Generator shows up to 150 keyword ideas. Just enter a broad topic, choose your target country, and hit “Find keywords.” 

For example, search for “bitcoin,” and you’ll see the 100 most popular keywords containing that word from our database of over 19 billion keywords:

You also see a list of the 50 most popular questions people are searching for:

Each list also has a Keyword Difficulty (KD) score for the first 10 keywords. The closer this is to 100, the harder it’ll be to rank for the keyword (more on this in point #9). 

Answer The Public uses autocomplete to find questions people are searching for. Just enter a broad topic, choose your target country, and hit “search.” 

For example, search for “bitcoin” and you’ll see 392 keyword ideas split into five categories:

Each category (except for alphabeticals) visualizes the keyword ideas like this:

Unfortunately, it doesn’t show keyword search volumes. However, the red circles next to each keyword (supposedly) tell you whether it gets a high, average, or low number of monthly searches.

ChatGPT is a chatbot from OpenAI. It’s not very useful for keyword research as a whole, but it is useful for finding seed keyword ideas.

For example, if you ask for a list of terms related to bitcoin, here’s what it comes up with:

Not all these are good seed keywords because they’re too generic and have multiple meanings (e.g., “fork”), but some are. 

For example, suppose you plug a not-so-obvious seed like “hashrate” into our free keyword generator. In this case, it looks like many people are searching for the hashrates of different mining hardware:

Unless you know the crypto industry inside out, you probably wouldn’t have thought of this seed keyword or discovered these keyword ideas.

Ahrefs Webmaster Tools shows all the keywords you currently rank for in the top 100. Just go to the Organic keywords report in Site Explorer.

There are many ways to use this report for keyword research, but one of my favorites is to find low-hanging page two rankings. To do this, filter for keywords in positions 11-20 and toggle the “Main positions only” switch.

As hardly anyone clicks on page two results, boosting your rankings for these keywords by just a few positions to page one can often massively boost traffic.

For example, we rank in position 11 for “pagerank”:

By applying our SEO checklist to this post or refreshing and republishing the content, we could likely hit the first page for this keyword and get way more traffic.

Google Keyword Planner is a keyword research tool for advertisers. But you can also use it to find keywords for SEO. It’s particularly useful for finding related keywords that don’t contain your seed keyword.

For example, search for “crypto,” and it kicks back ideas like “altcoin” and “safemoon coin”:

In fact, of the 880 keyword ideas found by Keyword Planner, 735 don’t contain the seed keyword “cryptocurrency.” 

Unfortunately, Keyword Planner only gives search volume ranges instead of exact volumes (unless you’re running search ads). But you can always copy and paste ideas into Ahrefs’ free keyword generator for a more accurate estimate.

Google Search Console (GSC) shows how your website performs for its top 1,000 keywords in organic search. Just go to the Search results report. 

There are many ways to use this report for keyword research, but one way is to find declining keywords that need your attention.

For example, if we compare the last three months’ performance for the Ahrefs Blog to the same period last year and sort the table by “Clicks Difference” from high to low, we can see that we’ve lost the most clicks from the query “google keyword planner”:

To try to fix this, we recently updated and republished our guide to Google Keyword Planner—and it worked.

Here are the clicks from that keyword for the past two months:

This shows how there’s sometimes more to gain from retargeting old keywords than going after new ones.

Google Trends visualizes the relative search popularity of a keyword over time. It also shows related rising and breakout searches. This is useful for finding trending keywords.

For example, search for “ai content,” and you will see a massive spike in interest recently:

If you then scroll down to the “Related queries” section, you’ll see rising and breakout keywords like “ai content creator,” “open ai,” and “chatgpt”:

There’s often a delay before trending keywords like these appear in traditional keyword research tools, making Google Trends a neat way to find newly popular topics before your competitors.

SERP Checker shows the top-ranking pages for (almost) any keyword, plus useful SEO metrics for the top three pages. It’s particularly useful for understanding a keyword’s traffic potential.

For example, Keyword Generator shows that “best bitcoin mining rig” has an average monthly search volume of 500 in the U.S.:

But if you plug this keyword into SERP Checker, you see that the top three search results get between 1K and 1.8K estimated monthly search visits. That’s 2-4X more than the keyword’s search volume.

This happens because pages tend to rank for (and get traffic from) many keywords, not just one.

Because of this, the estimated search traffic to the top-ranking pages is usually a better proxy of a keyword’s true traffic potential than search volume. So it’s worth plugging promising keyword ideas into SERP Checker to better understand how much traffic you can get by ranking.

Keyword Difficulty (KD) Checker estimates how hard it will be to rank in the top 10.

For example, the KD score for “bitcoin” is 99/100, meaning it’s super hard to rank for:

Yet the KD score for “litecoin vs bitcoin” is only 9/100, so it should be quite easy to rank for: 

That said, KD is based solely on backlinks. It doesn’t consider anything else that may affect ranking difficulty, such as content quality.

Because of this, a high KD score just means you’ll likely need lots of backlinks to compete. You should always investigate ranking difficulty further before going after a keyword.

Free vs. paid keyword tools: how do they compare?

Free keyword research tools are super useful when you’re just starting out. Still, the number of keyword ideas and data they show will always pale compared to paid tools.

For example, search for “bitcoin” in our free keyword generator, and you’ll get 150 keyword ideas. But if you search for the same seed in our paid keyword research tool, Keywords Explorer, and go to the Matching terms report, you get 763,256 keyword ideas:

Plus, there are a bunch of filters to help you find the best ideas for your website. 

For example, if you have a new website, you might want to find low-difficulty keywords with good search volume and traffic potential. You can do this in seconds by applying Keyword Difficulty (KD), volume, and Traffic Potential (TP) filters. 

From there, you can easily check the top-ranking pages to assess the competition. Just click the “SERP” dropdown or click the keyword and scroll to the SERP overview:

Final thoughts

If you’re new to SEO, free keyword research tools will be enough to discover some good keyword ideas for your website. But once your website grows and the value of your time skyrockets, paid keyword research tools are worth every penny. 

This is because paid keyword tools give you more data and allow for more efficient workflows, so you can find better keyword ideas in less time. 

Looking to learn more about keyword research? Read our beginner’s guide to keyword research or watch this video:

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