If you've ever launched a website, published content, or sold something online, you know search engine optimization (SEO) is key to getting eyes on what you build. And keyword research is a core part of optimizing your site.
There's no shortage of tools purpose-built for keyword research (literally hundreds of them), and they run the gamut from beginner-focused to highly advanced. They also range from totally basic and unhelpful to super valuable.
When done right, the best SEO keyword research tools simplify and streamline your SEO workflow. They make it easier to find the right keywords to target and give you the data you need to actually rank for them. When done poorly, they can complicate your search and slow you down.
That's why it's important to choose the right keyword planner tool. To help, we considered over 50 tools for keyword research. After in-depth testing, here are the eight best, including the all-around greats and apps built for more specific use cases.
The best SEO keyword research tools in 2021
Moz Keyword Explorer for the best all-around SEO keyword research tool
Semrush for advanced SEO professionals
Wincher for optimizing your entire website
RankIQ for creating SEO-driven content
GetKeywords for local SEO keyword research
QuestionDB for finding question-based keywords
Jaaxy for affiliate marketers
Keyword Surfer for an SEO keyword research browser extension
What makes a great SEO keyword research tool?
How we evaluate and test apps
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The features that make for a great keyword research tool are pretty straightforward: you search for a given keyword, and the tool tells you about it. But there are so many different ways to use keyword data, so we wanted to find tools that could handle a variety of use cases, along with a few designed for some of the most popular uses for keyword research.
During testing, we looked primarily at the factors below to determine which apps made our list.
Data included. The best keyword research tools give you all the data you need to rank for your chosen keyword. All of the apps we selected include, at minimum, traffic, keyword difficulty, and competitive SERP analysis.
Data sources. You should be able to trust that your keyword data is free of errors and biases, so considering where the data in each keyword research tool comes from was an important step for us. Every tool we included pulls data in from Google at a minimum.
Keyword optimization guidance. You shouldn't have to be a 10-year SEO industry veteran to use keyword research tools—the best tools offer simple, straightforward suggestions to optimize for your keywords. There are tools (like Ahrefs, Semrush, and Moz) that do complete SEO analysis on your site, checking for everything from site speed and technical details to domain authority and topic clusters. That's not what we're looking for here. We're looking for tools that any business owner or marketer can use to quickly understand their target keyword and optimize their site to rank for it.
Affordability. SEO software can get pricey, so we narrowed down our list to include only those keyword research tools that are within reach for the average SMB. All the tools below offer a plan at or below $120 per month, and most of them offer a free version of some kind.
What about Google's free keyword tools?
You may have noticed that none of Google's free keyword tools made our list—that's not an oversight. While several Google tools include keyword research features, they fall into two buckets:
PPC-focused tools (like Google Keyword Planner) that focus on search ads, including metrics like cost-per-click and competitive ad analysis.
Keyword tracking tools (like Google Analytics and Google Search Console) that monitor the keywords your site already ranks for.
If you're looking for an app that fits into either of those buckets, Google's free tools are absolutely worth a try. But for this roundup, we wanted to focus specifically on keyword tools designed for the research phase for organic SEO keywords.
The best keyword research tool overall
Moz Keyword Explorer (Web)
Moz's SEO platform offers several different tools designed for keyword research. While Moz doesn't include as many data points as some of the other full-featured SEO tools (like SERP position history or the total number of keywords a competing result ranks for), we consider that a benefit. It makes for a less overwhelming user experience for those who aren't professional search marketers, without skimping on the metrics you really want.
With the Keyword Planner tool, you can search any keyword you choose and see its monthly volume, difficulty, and organic clickthrough rate (CTR). Scroll down from there to see analysis of current results ranking for it and suggestions for similar keywords.
Here's our favorite feature: Moz includes a "Priority" score that simplifies keyword research by giving you the bottom line on whether a keyword is worth chasing for you. Moz automatically calculates the score based on the keyword's volume, organic CTR, and difficulty, along with your "My Score"—a metric you set yourself, designating how important a given keyword is to your business, based on your own expertise and knowledge of your business and industry.
Moz Pricing: Keyword research features are available for free for up to 10 queries per month; Moz Pro plans start at $99/month for 150 keyword queries per month
Ahrefs and SE Ranking are also popular SEO platforms with keyword research features comparable to Moz. While we tested all three, we found Moz to be the most user-friendly of the group. Moz also shares a few metrics (like organic clickthrough rate and their Priority score) that make it more valuable, particularly for people who aren't professional SEOs. But the others are definitely worth a try to see if you prefer them—SE Ranking specifically has more affordable pricing.
The best keyword research tool for competitive keyword analysis
It's the most expensive tool on our list, but if you're looking for something more advanced, Semrush shares a ton of keyword data and makes it easy to dig into the details, like SERP features (featured snippet, reviews, site links, image pack, and so on) and granular analysis of current results.
Semrush offers a broad range of keyword research tools, too, from the standard traffic and search volume data to content-driven keyword research and competitive keyword gap analysis.
That competitive keyword analysis is really what sets Semrush apart. With the Keyword Gap feature, you can enter your competitors' websites and Semrush audits the keywords they rank for that you don't—making it easy to find new opportunities.
As an added bonus, the SEO Content Template tool lets you optimize content as you write by grading your content in real-time for readability, originality, tone of voice, and SEO: it uses a handy bullseye graphic to help you strike the right balance. Plus, the tool visually checks off SEO recommendations (like using your target and related keywords and adding relevant links and images) as you go.
Semrush Pricing: Plans start at $119.95/month for up 3,000 results per day and 250 keyword metrics updates per month
The best keyword research tool for optimizing SEO for your entire website
Wincher is a great option if you're looking to optimize your whole website, identifying keyword opportunities and tracking your ranking progress.
To start, you'll enter your website domain. Once the data loads, click Keyword Research in the left-hand menu to see a whole list of Wincher's keyword suggestions. These are keywords your website already ranks for, but you can filter by position to find keywords beyond the top 10—keywords you can optimize for to move up in the rankings. You can further prioritize your updates by filtering based on traffic or volume, competition, and cost per click (CPC).
Switch over to the Related keywords tab for more traditional research on specific keywords—whether or not you already rank for them. For any keyword, click on the three dots on the right-hand side of the relevant keyword and choose Add keywords to track your rise through the SERPs.
Wincher Pricing: Plans start at 29€/month for daily ranking updates and up to 10 websites
The best keyword research tool for SEO-driven content
RankIQ is built for content creators who aren't SEO pros. Instead of showing you a whole list of granular metrics, the tool uses AI to analyze keyword data and serve up simplified, bottom-line recommendations for creating blog posts that rank.
To start, you can browse RankIQ's targeted Keyword Library, filtering by blog niche (from beekeeping to business automation) to find keywords that are pre-vetted for high traffic potential and low competition.
Once you have a keyword in mind, you'll create a report. There, you'll see straightforward suggestions for word count, topics to cover, and how to write your title. Below that, RankIQ compiles content with the highest "content grade" to help you structure and inspire your content.
When you're ready to build your outline and get writing, you can click over to the Content Optimizer tab. At the top, you'll see the current grade and word count, along with the recommendations for each. Down the right-hand side, you'll see topics to include. Once you cover them, you'll see a green checkmark appear.
RankIQ Pricing: The Lite plan starts at $29/month for 8 monthly reports
The best keyword research tool for local SEO
GetKeywords is a keyword research tool built to help with local SEO keywords. When you type in your target keyword, you can narrow results down to the country, state/province, or even city level.
You'll see the top locations within each country or state you search in, as well as the breakdown of mobile and desktop traffic. If you're a local business, this is super valuable because it allows you to avoid wasting time chasing keywords that no one nearby is searching for.
Scroll down to see related keywords grouped by search intent, including video searches, eCommerce, and question-based searches.
One of our favorite GetKeywords features is a little further down, where the tool tells you the average bounce rate and organic click rate for the SERP as a whole. That means you can decide right away if a given keyword is worth trying to rank for and set realistic goals.
GetKeywords Pricing: The free version includes unlimited keyword searches, filtering down to the city level, top devices and questions, and related keywords; paid plans start at $24/month and unlock additional keyword data like SEO difficulty and competitor keywords
The best keyword research tool for finding question-based SEO keywords
QuestionDB is among the leanest tools we tested. As the name suggests, you type a keyword or broader topic into the tool, and it brings up a list of related questions people ask online.
What's unique about QuestionDB is the sourcing. While several tools will show you question-based keywords pulled from Google or Bing, QuestionDB scrapes questions from all across the web, including sites like Reddit, Quora, and Stack Exchange—which, of course, are a gold mine of questions.
For example, you might search for a topic like "keyword research." QuestionDB will scrape the web to find common questions people are asking related to keyword research, enabling you to see how, why, and where people are talking about the topic. You can brainstorm content topics, see how people are talking about a topic outside the Google search bar, and get more context on how you should talk about the topic.
QuestionDB Pricing: Free for up to 50 results per search; Pro plan includes complete results (up to 800 per search) and unlimited searches for $10/month
The best keyword research tool for affiliate marketers
Jaaxy's keyword research tool is pretty straightforward: type in a keyword, topic, or URL, and the tool will give you a list of related and suggested keywords, along with basic stats on each (think average monthly search volume and traffic to page 1 results).
Jaaxy offers a unique Domains column, where you can see the .com, .net, and .org domain names related to each keyword that are available to buy. (Note: we weren't able to test this feature during our trial.)
What stood out for us was that Jaaxy helps you find affiliate programs to join and feature on your site. Switch over to the Affiliate Programs tab, and enter your keyword to see a list of affiliate programs sourced from Commission Junction, Link Share, Digital River, and Click Bank. Jaaxy also shows you the listed commission and Alexa Rank for each program and associated product website.
Jaaxy Pricing: The first 30 searches are free on the limited Starter trial; paid plans start at $49/month
The best browser extension for lightweight SEO keyword research
Keyword Surfer (Chrome)
Browser extensions offer a lightweight way to do keyword research without ever leaving the search engine results page. Keyword Surfer, a Google Chrome extension from Surfer SEO, is separate from the full SEO suite and offers a limited version of the platform for free.
Once you download and enable the extension, head to Google and search for your keyword the same way you'd do a normal Google search—you'll see estimated search volume and CPC data populate in the search bar as you type. Hit enter to see the same info, plus the number of exact match keywords on the page for each SERP listing.
Related keywords and visualizations of the SERP data are on the right-hand side. Also on the right, you can click to open the Content Editor and start writing your content. You'll see all the LSI (latent semantic indexing) terms you should include on the right—highlighted in red until you add them, then green.
If you opt for the full Surfer SEO app, you'll also see an overall "Content Score" plus suggestions on how many headings, paragraphs, and images to include.
Keyword Surfer Pricing: The Chrome extension and limited content editor are free; paid plans of the full Surfer SEO suite start at $59/month for the full content editor (with 25 queries/month), SERP analyzer, and other SEO features