The 9 Best Free Keyword Research Tools

Joshua Hardwick
Head of Content @ Ahrefs (or, in plain English, I'm the guy responsible for ensuring that every blog post we publish is EPIC).
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    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.” 

    Ahrefs' free keyword generator

    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:

    100 bitcoin-related keyword ideas

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

    50 bitcoin-related keyword ideas phrased as questions

    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). 

    Keyword ideas too broad? Feed them back into the generator

    Let’s say you enter “bitcoin,” and the generator kicks back “bitcoin mining.” If you want to explore that topic further, feed it back into the generator. If you want to go even narrower, do another round.

    Feed keyword ideas back into the keyword generator to explore that topic further

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

    Answer The Public homepage

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

    392 bitcoin-related keyword ideas

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

    Keyword ideas visualization

    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.

    Keyword color codes
    Looking for actual search volumes?

    Paste keyword ideas from Answer The Public into Ahrefs’ free keyword generator. The first keyword on the list will usually be the one you entered, and you’ll see its search volume.

    Use Ahrefs' keyword generator to get actual search volumes

    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:

    Seed keyword ideas, via ChatGPT

    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:

    Search volumes, via Ahrefs' free keyword generator

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

    Getting underwhelming results from your ChatGPT prompts?

    Don’t ask for keyword ideas. Ask for terms related to a topic by starting your prompt with “give me a list of terms related to…” 

    How to find better seed keywords in ChatGPT

    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.

    64,120 keyword rankings for the Ahrefs Blog, via Ahrefs Webmaster Tools

    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.

    Filtering for low-hanging keyword opportunities

    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”:

    Example of a low-hanging keyword opportunity

    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.

    Not sure which keywords to prioritize?

    If you have thousands of page two rankings, prioritize keywords with the highest “business potential.”

    How to score a keyword's business potential

    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”:

    Keyword ideas, via Google Keyword Planner

    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.

    Search volumes, via Ahrefs' free keyword generator
    Looking for even more related keywords?

    Instead of starting with a seed keyword, start with a seed website. 

    For example, suppose you use bitcoin.org as the seed site. In that case, you get some hyper-specific keyword ideas that you might easily overlook in “conventional” keyword research tools. 

    Enter a seed site to find keyword ideas you might otherwise overlook

    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. 

    Search results report in Google Search Console

    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”:

    Example of a declining keyword that could use our attention

    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:

    Results of our content refresh

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

    Don’t make the mistake of ignoring seasonality

    Make sure to choose a year-over-year comparison period in GSC. Otherwise, you risk seeing skewed numbers due to seasonality. 

    For example, our traffic always dips in December when people are off enjoying the holiday season. If we were to compare the first and last six months of the year, the numbers would be skewed and might lead us astray.

    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:

    Trend for "ai content," via Google Trends

    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”:

    Breakout topics related to AI content

    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.

    Looking for specific ideas related to trending topics?

    Just plug a rising topic back into Google Trends.

    For example, if you put “chatgpt” (a rising topic from our search) into Google Trends, you see more specific things people are searching for around that topic. 

    Results of plugging a rising topic back into Google Trends

    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.:

    Estimated monthly search volume for "best bitcoin mining rig," via Ahrefs' free keyword generator

    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.

    SERP overview for "best bitcoin mining rig," via Ahrefs' free SERP checker

    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.

    Do top-ranking pages get less traffic than the keyword’s search volume?

    Traffic potential isn’t always higher than a keyword’s search volume. Sometimes, it’s lower.

    For example, “how many people own bitcoin” gets an estimated 1.4K monthly searches in the U.S., but SERP Checker shows that the top-rankings get significantly less traffic than this—despite ranking for hundreds of keywords: 

    SERP overview for "how many people own bitcoin," via Ahrefs' free SERP checker

    There are many reasons this can happen. In this case, it’s probably because Google answers the question on the SERP, so most searchers don’t need to click a result.

    Example of Google showing the answer on the SERP

    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:

    Keyword Difficulty for "bitcoin," via Ahrefs' free KD checker

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

    Keyword Difficulty for "litecoin vs bitcoin," via Ahrefs' free KD checker

    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.

    Looking for a rough estimate of how many backlinks you need?

    Check the estimate below the Keyword Difficulty (KD) score. 

    Estimated number of websites you'll need backlinks from to rank in the top 10 for "litecoin vs bitcoin"

    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:

    Over 763,000 keyword ideas related to "bitcoin," via Ahrefs' Keywords Explorer

    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. 

    Filtering for low-difficulty keywords with high traffic potential

    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:

    Analyzing competitors via 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:

    Did I miss any good free keyword research tools? Ping me on Twitter.

    • Monthly traffic 19,870
    • Linking websites 1,234
    • Tweets 280
    Data from Content Explorer