11 Best Keyword Research Tools for SEO [2019 Review]

There is no denying that keyword is the center of the Search Optimization Engine (SEO)

Every SEO marketer uses keywords and search phrases to push the content of their website to the front page of Google, the leading online search engine for product and service.

Now you will agree with me that

To have your website appeared on the first page of Google, you need to know how to use the keyword research tool to pick out the best keyword for your content.

That is why this extensive guide concentrates on the best keyword research tools on the market. This guide is your ultimate key to a successful SEO strategy.

Read the list of the best SEO tools now and find out which one is suitable for your needs.

11 best SEO keyword research tools you have to know

1. Google Keyword Planner <Free>

google keyword planner

Google Keyword Planner is the foundation of the keyword tool and also is the most used tool in the market. It connects straight into Google Adwords, which makes it cost-efficient when you want to find out and optimize your cost per click keyword.


  • It has remained free of charge throughout the course of development. The users can use all the available features without any extra cost.
  • Being the main search engine with a massive backbone database, Google Keywords Planner is robust in tracking and add new keywords to the database.
  • It also provides a trending system where each keyword will show their respective up trend or down trend. You will always get the best trending keywords of the month.
  • There is a new feature that allows the users to view the location of the popular content. You can now know what specific keywords to use in a particular region. It is a good option for local businesses.


  • It requires you to have a website set up already.
  • Due to the sheer amount of keywords database, it updates the trending words in the period of more than three months.
  • It might not be suitable for someone who looks for short-term trending keywords.
  • It does not provide what keyword appears on which target device anymore.

Despite some inconvenient setback, it is still of the most popular keyword research tools. Use it for free right now with the following step:

How to use Google Keyword Planner

2. Google Trend <Free>

google trend

If you want to run a good business on the internet, it is essential to keep track of your website’s traffic.

The website’s traffic can show you the trending performance of your site in the real time. You will understand why people come to your website, what specific topic they are interested in at the time.

The professionals can also analyze the web’s traffic to find out the right traffic pattern to guide their website posting strategy as well as determine on what trending is influential in the month.

That is why Google Trends becomes one of the most helpful tools for website traffic tracking.

Do not worry if you never use Google Trends before. Below is the comparison to get you straight into the advantages and disadvantages of using Google Trends.


  • Depict Real-Time data on any particular topic thanks to the massive Google database.
  • There are always new and innovative features added to Google Trends by the best of Google engineers.
  • Reveal the latest trends from all over the world at ease.
  • Clean and straightforward visualized data to get used to, especially if you are a beginner. Easy to navigate to other options such as reporting, forecasting, etc.


  • Because Google Trends is still the proprietary service of Google, they do not reveal how the trend calculation is done in the back end. You have to believe in what you get.
  • Because the data is already aggregated on the large scale of number, sometimes there might be missed insights on the specific niche market that you are interested in.

Thanks to the tool being completely free of charge, it is strongly recommended that you try out the Google Trends to make sure all your keywords are matching the upward trending direction.

You will see that it is very easy to use this tool.

Check out the Google Trend here

3. KWFinders <Worth $29.9-$79.9>

KWFinders is the brilliant SEO solution which heavily focuses on the keyword cluster recommendation.

If you need to identify the keywords to base your marketing strategy around the best keyword with low SEO difficulty, KWFinders provides the most satisfying solution in just a few clicks.


  • The free options are effective enough for small scaled users.
  • From the first glance, you can tell the user interface is carefully designed. You can quickly type out your keyword and KWFinders will instantly give out the suggestion to improve it.
  • KWFinders offers you three different methods to find out the best keyword that suits your needs. This flexibility is well-developed to give you the most bang for your bucks.
  • There are options to search for trending keywords and volume keywords. They are available for free.
  • The keyword difficulty score is explicitly described to get you to understand the topic of how to choose the right competitive keyword in the market.


  • Unlike Google Keywords Planner, the tool is not entirely free. There is a limit of keywords that you can research per day on the free base usage.
  • There is no option for competitor research. You cannot search what keywords your competitor is using.
  • There are no options for searching multiple keywords on different tabs. You can only perform one search operation per one keyword.

Do not hesitate to try out KWfinders. Thanks to the free option without any registration process, KWFinders makes it convenient for anyone to try, from beginner to professional SEO marketer.

Head on to KWFinder to find your best keywords now.

4. SEMRush <Worth $199>


SEMRush has been the popular SEO tool since 2008.

SEMRush has its competitive edge built up the competitive intelligence. The tool provides the complete all-rounded options for SEO strategy including backlink profile, keyword optimization, and domain analysis.


  • SemRush generates transparent data analytics and visualization sheets, which let the users optimize upon to result in the right strategic direction.
  • Besides the classic option of long tail keyword research, SEMRush also provides powerful options such as SEM analysis and SERP reports.
  • SEMRush provides a clear semantic usage for the general base users. You do not need to be a professional to understand SEMRush data.
  • There is a new option for Backlink data on SEMRush. You can monitor the appearance of your backlink profile as well as their click performance daily.
  • Can be integrated into Trello, a favorite planning tool used in businesses of all sizes.


  • There are sometimes reported problems of Keyword mismatch, especially when there are updated features in SEMRush
  • Sometimes the speed of keyword analysis can appear slow.
  • Requires more expensive options to unlock the complete SEMRush powerful features.

If you desire more than the limited option that other free SEO tools have, then there is no time to waste. Get yourself a premium SEMRush account to enjoy all the best SEO options that this amazing tool provides.

Try a 14-day (completely free) trial of SEMRUSH here

5. Ahrefs Keyword Explore tool <7-day trial for $7>

Ahrefs is leading the market of SEO tool at the moment on the competitor research aspect.

If you need to view the entire SEO strategy, keyword selection and how your competitor sets up their backlinks, Ahrefs can offer you all of these powerful options within a few clicks.

Continue to read on the pros and cons of Ahrefs to understand why it is the best tool for competitor research.



  • Ahrefs got the most extensive web crawler database in all of the SEO tools, which makes them provide the professional keywords with high accuracy.
  • Also thanks to the massive web crawler database, Ahrefs is the only tool with the best option to find out what keywords your competitors are using at the moment.
  • Ahrefs also possesses a massive backlink database, which clearly depicts how well your backlink is performing in real time update.
  • Not just dumping out the massive database on your web interface, Ahrefs also provides robust filtering tool to let you know which keyword cluster is the most important to focus on.


  • There is no free option to test any service from Ahrefs. You have to pay even for a 7-day trial test.
  • The lowest paying option is still not good enough because there are many limits and constraints.
  • Only suitable for large enterprise who can afford to pay more than $150 per month for the keyword research operation.

If you have set a strong budget and wanted to use the best premium SEO tool on the internet, then Ahrefs is the perfect solution for you.

Create your new Ahrefs premium account and start your brand new SEO strategy now.

Take 7 days trial of Ahrefs for $7

6. Spyfu <Start from $33/mo>

As the name suggests, SpyFu aims to provide its user the competitive edge by spying on the insights of competitor’s website.


You can learn more about how Spyfu can help you compare the strength and weakness of your content against those of your competitor.


  • Excellent and robust reporting tool that allows quick access to keyword information and pay-per-click history that is related to the keyword.
  • The new Kombat feature of Spyfu stands out from other keyword tools. They show the concept of “Shared keywords” which let you understand more about the overall market research and keyword recommendations
  • Spyfu is also one of the tools that provide information about competitor’s keywords and ads. This is a crucial service if you set up your website in a competitive segment of product and service.
  • It is easy to use. You can set up your ads campaign with ease. You can also monitor your competitor’s ads campaign.


  • The database appears to be not big enough. Sometimes there are missing data on a few websites so the resulted keywords might not be accurate.
  • There is no support to export out the final charts and graphs. Only the raw data is extracted without other visualization graphics.
  • Free services are still restricted and not as good as other tools’ free service.
  • There is no support for the mobile version; you might have some problems with the UI screen when you view the data from your mobile phone.

Stop imagining how your competitor can push out a successful SEO strategy. Create a Spyfu account to view their strategy and get the secret know-how now.

Visit SpyFu

7. Serpstat

Designed cleverly to innovate in the market of SEO tool, Serpstat’s most distinguished feature is the insights of traffic flow on various domains.

The tracking option of Serpstat massively evolves around historical researching data. It reveals what the users have been searching in the past in a peculiar demographics then generates the new SEO strategy based on this ranking history.

If you continue to read the pros and cons of Serpstat below, you will agree that it is such a brilliant tool to have in your SEO repertoire.



  • Serpstat provides an insightful comprehension of the traffic distribution among the website domains. This is a fundamental feature to make Serpstat different from other tools.
  • Additionally, there are features such as rank tracking and keyword cluster which allow users to get the exact and precise information about the market share of each website domain. Then you will know which keywords to choose for which peculiar field.
  • Nonetheless, the most useful feature of Serpstat is “Missing Keywords.” You only provide the input of any of your post content and Serpstat will show you the missing keywords that you should be used to increase the ranking of your website.
  • You can also research the missing keywords of your competitor, which gives you a huge competitive edge over your competitors.


  • Within the free usage, there is a daily limit of the keyword query. You cannot perform research operation on many keywords.
  • The fundamental keyword difficulty is still in development, which might be a huge miss compared to other keyword tools.
  • The basic plan of Serpstat does not provide enough information about the keyword cluster.

Overall, Serpstats is a decent tool to test out the results of your keywords in comparison with other tools. It is the best way to confirm that you are using the best keywords for your business.

Just try out Serpstats free option now to see how you might feel about it.

How to use Serpstat

  • Head on to the https://serpstat.com/
  • Enter the keywords, domain or link so you can see the keyword analysis.
  • Using the free options to change and optimize your keywords.

Try SerpStats now

8. Soovle


Soovle captivates the user’s interest based on its simple motto “Let the web help.” To make itself stand out from other SEO tools, Soovle takes a creative turn to combine all of the most popular search engines to derive out the best keyword cluster.

Check out the pros and cons of Soovle to appreciate how simplicity can give you a starting boost in your SEO campaign


  • Only focuses on 15 biggest online search engines. This makes Soovle provide the fastest results of any given keywords.
  • The users can add in extra search engines (such as Amazon, Ask, Yell, etc.) to broaden their keywords research.
  • You can see the results immediately on real-time update from different engines. There is no waiting time on the keyword analysis.
  • Completely free of charge and simple to use. You can have the most popular topics or keyword cluster to choose from based on what search engine you want.


  • The UI appearance might seem a bit lacking and less professional compared to other keyword tools.
  • There are no powerful options such as domain research, backlink tracking, etc. Soovle is more suitable when you want a quick keyword cluster and idea before using other professional tools to do a complete analysis of these keywords.

If you want to get a simple concept based on the main keywords, Soovle is the key to unlock the door to your long-term SEO strategy. Navigate to https://soovle.com/ for the brainstorming idea of your next SEO campaign now.

9. Keywordtool.io


Keywordtool.io proudly presents themselves at the alternative for Google Keyword Planner for all SEO marketers, from amateur to professional.

Unlike the Google Keyword Planner that focuses more on the massive search volume of keywords, Keywordtool.io delivers more descriptive keywords based on the niche topic of every keyword.

As a result, the keyword suggestion generated by Keywordtool.io possesses the best combination of low SEO difficulty and high domain ranking score.

Continue reading as you are guaranteed to know the inside out of this all-rounded SEO tool.


  • You do not need to register an account to use Keywordtool.io. The primary tool is entirely browser-based. Just enter any keyword you need into the search bar to start the analyzing process instantly.
  • io can generates more than 750 keywords on one go. You can actually view all of the 750 keywords easily.
  • The tool also focuses heavily on the long tail keywords, which is the most important category of keyword research. Most of the tool’s suggested keywords are long tail keywords


  • The free version is too limited. There is no other information besides the raw value of each keyword.
  • You cannot view Search Volume or Keyword Difficulty score without premium account.

If you do not mind spending the budget on the premium account, Keywordtool.io deserves its name as the Google Keyword Planner alternative. Use it now.

10. Moz keyword explorer

Moz is a new and upcoming SEO platform that provides all the crucial marketing insights via keyword input optimization.

Moreover, besides tracking the performance of keyword on domain and website channel. Moz also reveals how the keywords are shared through the social network.

moz keyword explorer


  • The interface is intuitive, easy to use and navigate.
  • There is a good option to view through the crawling database, which provides insights into what keyword your competitors are using.
  • The Backlink option is robust and powerful – not only does it reveal very backlink profile to your website, but it also provides the SEO strength, weakness, and difficulty of each backlinking domain.
  • Nonetheless, Moz keyword explorer also includes a Google Chrome extension which helps you monitor Pagerank and SERP.


  • Require a signed up account to use.
  • A free account only allows 10 queries per month, which is very limited compared to other free keyword tools.

Do not be discouraged because you must register a free account to use the Moz keyword tool. It is worth a try because of the massive site crawling database and the fantastic backlink analysis solution.

Head on to the https://moz.com to research your keywords now.

Using the right tool for the right job

Now you must have the overall knowledge of all the best keyword tools in the market.

If you are still confused about what tool to pick, do not worry.

Follow this simple advice.

Set out your budget before hand.

If you just start out your SEO career or you are still looking for a new strategy for for SEO campaign, using the free keyword tools is very convenient as you get the chance to find out what works best for you.

If you have more experience and can afford the premium tools, pick out those that fit your bill to enjoy the robust and powerful options from the premium version of SEO tool, including the ability to figure out what keyword your competitors are using.

That all !!! If you like this post on Affiliate Solo, please comment and share it to everyone. Thanks

About the Author Roger Le

I am a former student of an University about Technology and science based in Vietnam. Working mostly in the environment surrounded by the Internet, I soon realized the world is borderless.I got inspired with affiliate marketing and spend most of my spare time working on it.I am here now to bring you this delicate website that I’ve invested my heart and soul.

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