Introduction and Glossary

My guess is that you are on a mission. And the goal of that mission is: To find the best keyword research tool on the market.

First of all: Congratulations!

You recognized the immense potential to generate traffic through a thorough keyword research.

We at SEOintheSUN have been using at least 5 different keyword research tools in the last 7 years but we were always unsure about our choice.

Now in 2018, there are more tools than ever on the market. So we started a new journey trying to figure out which is the right fit for ourselves and our clients.

First, we thought how to do this. Then we took a pragmatic approach: Test them all! And we let them compete against each other and compiled the results in an academic research.

We had many questions and those were our disciplines right there:

  • Keyword Suggestions: How many does each tool give us?
  • Search Volume: Which tool gives us the highest total amount?
  • Relevance: Are the suggestions relevant to the search intent?
  • Uniqueness: Did the keywords pop up in several tools or just one?
  • Data Sources: Where does keyword data come from and how credible is it?
  • Reports and Settings: What are our options in each tool?
  • Time: How long does the keyword research process take?

On top, we had two major criteria when looking into each tool. They don’t affect everybody but are interesting for those of you who need to attract international clients.

1) “Can the tool show us aggregated numbers on a global level across all territories and languages?”

Why do we care? Because we get visitors from around the world. Many search in English and we want to target all of them with one single blog post.

2) “How does the tool perform in other countries and languages in general.”

We care because we don’t just operate in one country and need to know what people are searching for in many languages. Especially in our three main ones: English, German and Spanish.
They are also the main pillars of this study as we translated our seed keyword “learn german” into German (“deutsch lernen”) and Spanish (“aprender aleman”).

Actually, SEOintheSUN is a digital marketing school and agency and part of the FU International Academy, a company based in Tenerife (Spain) with a couple of different offers for international clients.

FU International Academy

Our global mindset made us take a look at the tools from such an international perspective. But after long hours of research, we still had too many questions unanswered. The content out there just didn’t fully fit our situation.

So we decided to do our own investigation of the topic. What you’re reading right now is the result.

We tell you all about the process we went through to decide which is the best keyword research tool for ourselves. And how to create the right service packages for the different needs of our clients.

Along the way, you’ll get some interesting insights into the tools and their data sources. But for now, let’s get the ball rolling and find you your personal best keyword research tool!

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Outline and TL-DR

This post includes affiliate links to tools and products we use and love. If you buy something through those links, we might get some extra coffee money (at no extra cost for you!) which helps us create more awesome posts like this!

By the way.

We know that you’re all busy people and have no time (or interest) to digest an 11,000+ words study for breakfast. Still, we thought it makes sense to give you the full picture with the option to read it all. Or to skip it all. Whatever it takes to find your best keyword research tool.

If you want the get the gist of the matter at once skip to our Too Long – Didn’t Read part. It summarises everything in a 1,800 words conclusion.

Then again, if you’re in it for the long haul, take a look at the rest of our outline. You might notice that we took the good ol’ academic approach.

Don’t worry, you can rest assured that we won’t bore you with any more academic slang. You don’t care about the literature review? No problem, skip to the results or any section you’re interested in most.

In any way, one of our main goals here is to be transparent about our decision-making. Because let’s face it: We’re not almighty and always want to improve our processes. But to do so, we first have to show you how we work.

Along the way, you’ll understand how we designed our SEOintheSUN keyword research services. Or we might also help you to cut through the clutter and choose the right tool for yourself.

To be clear upfront – there are some things that this study can tell you and some that it can’t.
Have a sneak peek at your takeaways! 

Takeaways SEO Case Study
  • Quantitative Analysis: keyword suggestions and search volumes of different tools
  • Niche: numbers for broad seed keywords (language school niche)
    – “learn german”  | “deutsch lernen” | “aprender aleman” –
  • Data Sources: insights into differences between tools
  • International Context: tool comparison for worldwide searches
  • Paid vs. Free: advantages of paid tools over free alternatives
  • SEOintheSUN Services: insights into our processes
  • Features: no comprehensive demonstration of all tool features
  • Local Niche: no test with narrow seed keywords for local niches
  • Keyword Difficulty: no comparison of keyword difficulty metrics across tools (coming soon)

Still on board? Great.
If you want, take a brief look at the terms in our glossary, buckle up and let’s do this! Figure out your best keyword research tool!

Glossary: Terms and Metrics

To make your life easier, we put together a little glossary.

Here you find all the terms and abbreviations that you’ll encounter later on.

SV – Search Volume
The number of monthly searches for a certain keyword averaged over the past 12 months.

KW – Keyword
What this study is all about. We are looking for keywords to see which terms people put into Google. The trick is to understand what they actually intend to find with those terms.

SKW – Seed Keyword
The main keyword that you put into a tool to generate further ideas or keyword suggestions. Our seed keywords in this study are rather broad with: “learn german”, “deutsch lernen” and “aprender aleman”.

SERPs – Search Engine Results Pages
The results pages that show up in response to a Google search with a specific keyword. The first SERP includes the pages on the top 10 positions.

TKR – Traditional Keyword Research
A keyword research process that generates new keyword suggestions based on a seed keyword. Suggestions can come from different data sources as e.g. the Google AdWords API.

CKR – Competitive Keyword Research
A keyword research process that generates new keyword suggestions based on the keywords that competitor sites already rank for. Keywords are scraped from the SERP top 10 sites for a specific seed keyword.

API – Application Programming Interface
It basically serves as the intersection of two different software programs and helps them to interact. For example: Some keyword tools interact with Google to source their data.

Google AdWords API
An API that keyword tools can get in order to access Google Keyword Planner data.

Google AdWords
It’s a Pay Per Click advertising service by Google and its main revenue source. It lets you display ads on top of the organic search results.
The ad price is determined via a bidding process.

Organic SEO
It’s basically the opposite of paid advertising via Google AdWords.
You optimize your content in order to rank naturally in the Top SERP positions.

PPC – Pay Per Click
A payment model for online advertising services. The marketer only pays for successful ads. In essence, those that visitors clicked on to get to the landing page.

Close Variant
Close variants of a keyword usually have the same search intention but expressed with slightly different terms, e.g. SEO vs. Search Engine Optimisation.
The Google Keyword Planner combines or “groups” the search volumes of close variants in their metrics.

This way it’s impossible to break down how much search volume comes from which exact term. That’s hassle in content marketing when choosing the focus keyword.

Exact Match
It is usually used in the context of keyword metrics. This means for example that search volumes are not combined for close variants but only shown for the exactly the term that was entered into Google.
Paid keyword research tools like KWFinder disentangle this and show exact match data.

Clickstream Data
Clickstream data basically is all about which websites people visit on the internet and where they click. Tools like Ahrefs and Moz are using it in their models to predict keyword search volume data.

Total KWs – Total Keywords
The number of keywords that are exported from each tool. It’s the direct output without any filters.

RKWs – Repeated Keywords
Keyword suggestions that several tools provide, i.e. those that show up in more than one tool.

UKWs – Unique Keywords
Keywords that are uniquely found in a certain tool, i.e. keywords that only this one tool shows.

Rel. UKWs – Relevant Unique Keywords
Keywords that were left after we filtered the unique keywords for their relevance, i.e. if they actually fit the search intent of the seed keyword “learn german”.

KWs SV < 10 – Keywords with Search Volume below 10
The keywords that have a search volume below 10 in their tool. This metric includes many keywords with no search volume or no available data.

KWs with SKW – Keywords with Seed Keyword Phrase
Keywords that contain the seed keyword phrase. This metric shows if the tools simply add more phrases around the seed keyword or if they find alternative suggestions.
The latter may have the same search intent even if the seed keyword is not included.

Standardised Search Volumes
Each tool provided us with different search volume numbers. To assess the quality of each tool’s suggestions, we imported them to KWFinder and compared this standardized data.

USP – Unique Selling Point
It is the feature or characteristic of a product/service that makes it unique and sets it apart from all competitors. We defined the relevant unique keywords as USP of keyword research tools.

Literature Review and Tools

Okay, on to the next part – the literature review.

What does a literature review usually contain? It tells you what’s out there and which analyses other researchers did in the past.

To be honest, good and transparent studies in the SEO field seem to be a rarity. Only the big players appear to have the resources to invest the necessary time and effort. On top, they certainly won’t release everything they’ve got.

And why would they?

Let’s face it: In the end, all keyword research tools are selling a similar software. Why should they reveal valuable insights that they can use to outpace their competitors?

So all that’s left to do for us is to say:

SEO Knowledgebase Dream

We have a dream…

“We have a dream that one day we’ll have a structured knowledge base about SEO with transparent studies and scientific guidelines.”

Our Dream of a Knowledge Base in SEO

The competition between keyword research tools makes it hard to build a lasting knowledge base as e.g. in academia.

But there are even more obstacles in the way.

Which? Well think about this: As soon as marketers get close to getting a grasp of Google’s algorithm, a shiny new update changes the game.

Ergo: Some previous studies may become irrelevant faster than you think. But they still will linger around the web (it is content after all…) and that makes it hard to be confident about their accuracy.

Another thing to consider:
It might even go against the interests of some SEO providers to be transparent. Publically learning from your mistakes entails admitting them first. So our impression is that SEO studies are often a beauty contest of success stories at best.

Take a look at some of SEMrush’s case studies and you’ll see what we are talking about. Sure, they’re all interesting to read but also often built according to the same schema:

“See how we managed to increase [insert desired KPI] by XY % in XY time!”

Because in the end, even the best keyword research tool needs to keep the marketing engine going. This guest post in the Ahrefs blog sums up the dilemma quite well.

Up next, we tried to gather the ‘State of the Art’ of other interesting articles in keyword research. One major issue here is lacking transparency.

It’s quite hard to find out, how the different tools actually come up with the numbers that they throw at you. We gave it our best shot in the section on the Data Sources of Different Tools. Finally, we’ll introduce you to our Lineup of Competitors and their basic info.

Previous Studies about Keyword Research

There’ve been different kinds of research done in the SEO field so far.

On a macro level, you have the heavyweights like Moz and Ahrefs or SEMrush. They even conduct statistical correlation studies to figure out the most important ranking factors in Google. Or this case study here from the team of Moz which actually shows you well how SEO should be done in 2018.

But since we don’t want to overload you with information, we’ll stick to what our study is all about. Keyword research.

Of course, we didn’t reinvent the wheel here.
We’re not the first ones who thought about comparing the options to find the best keyword research tool. Have a look at some examples of what’s out there on the topic so far.

Firstly, their well-organized overview of SEO Tools was a great starting point. Especially when we tested different free keyword research options.

Beyond that, they even published a guide to keyword research. It includes a review of four of the tools that we also feature: SEMrush, SECockpit, Moz and Ahrefs. It’s a nice comparison to get an overview of their basic functionalities.

SEMrush also took a closer look at some of the tools in our comparison – of course including their own. Fair enough but what’s again missing is a quantitative analysis. What keywords do these tools actually cough up? Are they relevant to your niche?

Check out Authority Hacker by all means.

They did a great job at explaining all the features that keyword research tools offer. Including five of those in our comparison. So if you want to see what exact functions await you in the tools, read through their extensive reviews.

Following Authority Hacker, we also split our analysis in traditional keyword research and competitive keyword research.

“When should you take which keyword research approach?”

The traditional approach only gives you suggestions based on your seed keyword. Ideally, you’re looking for a keyword with solid search volume which is still not targeted by your competition.

This approach is in so far risky as you have no guarantee that those keywords work. But it certainly is the right pick for you if you’re a market pioneer and need to stay ahead of the competition. Or are you a casual/low-frequency blogger? Then it might not make sense to invest money into a competitive keyword research tool.

The competitive approach has the advantage that you spy on the keywords which work for your closest competitors! Based on your seed keyword, the tools check the first results page of Google and its top 10 domains. Then they scrape all the keywords that those domains are ranking for in addition to your seed keyword.

Do you have the same content quality and domain authority (or even better)? Then that’s a solid sign that you should be able to target and rank for those keywords as well.

Now we’re getting closer to what we’re aiming to do in this SEO case study:
Finding our perfect combination of keyword research tools. This blog post goes into that direction. It recounts how SEO practitioners actually are using the tools available at their agency.

The main takeaway: There is not THE one best tool. The safest bet is to combine suggestions found in different tools.

Having read these articles, we were still pondering. Which tool should we use for our services on a long-term basis?
Trying to make a choice, it hit us. A mere list of functions and screenshots won’t help us to decide that.

We were still missing something…

DATA and STATS to back our decision!

And that’s what we try to deliver ourselves right here, right now.

So we dove headfirst into the pool of keywords that the tools spit out and tried to tame them with Excel and Google Spreadsheets.

Now. When we speak about data of different keyword research tools, it gets tricky. Looking at keyword metrics, you probably already asked yourself at one point:

Where the hell do these numbers come from?

No worries, you’re not alone. Indeed, at first sight, data sources of the tools appear to be a black box.

We tackled the issue and shed some light on it now.

Blackbox Keyword Data

Data Sources of Keyword Research Tools

First things first.
Before we go any further, it’s time to level the playing field.

We need to clarify some basic distinctions in how and where each tool gets its data. Seriously, for us, the data sources were also the main source of confusion.

All right. Aiming to clear this up, we navigated through the world wide web for information and wrote to all of the companies.

To the best of our knowledge and research skills, there are two main groups of keyword research tools:

Those which source the concrete search volumes directly via the Google AdWords API (KWFinder, SECockpit, KeywordsEverywhere).

Those which combine basic Google data and improve it via third party clickstream data (Moz, Ahrefs).

To get the difference, you need to be aware of the latest developments with Google Keyword Planner.

To put it in a nutshell:

Google Keyword Planner in a Nutshell

Once upon a time in a land far far away, the Google Keyword Planner was the best option to source search volume data. This made the life of SEOs extremely easy. But that’s already where the fairy tale ends.

Because Google decided to turn the tables on all of us. They tied the access to this data to the amount of money spent on paid advertising in AdWords. Makes sense for Google but sucks for SEOs.

If you have no paid campaigns running, you’ll see only broad data ranges. In essence, they have little value for your keyword selection process.

Let’s face it: After all, it makes a difference if your target keyword has 11,000 or 99,000 searches!
But that’s the only range that Google will show you.

As a matter of fact, that’s why we don’t use Google Keyword Planner and didn’t include it in our comparison. We simply wanted to spend our time and energy on finding its best alternative!

Now. Some tools (KWFinder, SECockpit, KeywordsEverywhere) still have access to the specific search volumes via the Google AdWords API. Yet, that comes with A LOT of requirements that the tools must follow. Take a look for yourself here.

Some users of this API say that this forces tools to be geared more towards Pay Per Click instead of organic SEO.
That of course – again – especially entails one thing: More business and money for Google.
And even if tools put all the requirements in place, they are still at the mercy of Google. If they change the rules of the game, there’s nothing much you can do.

Fancy an example?

There are many Dirty Secrets of Google Keyword Planner. But why do we even care about numbers the Keyword Planner shows if we don’t even use it in the comparison?
Remember that its AdWords API is the principal data source for tools like KWFinder. So you should understand that it could also source potential problems along with it!

Especially one gave us headaches. The grouped search volume of similar keywords (or ‘close variants’).

Grouped search volumes mean for you: More noise in the numbers. You’ll, for example, see two similar keywords like “SEO” & “Search Engine Optimization” with the same search volume (100 K – 1 M). That’s not just a coincidence!

Chances are that Keyword Planner merged their search volumes. In essence, it shows the total volume sum of both keywords plus any other ‘close variants’. But you’re lacking information on which keywords are included in this data range and what their precise volume is.

Confusing? Yep! Intransparent? Exactly.

That’s the case because the Google AdWords search volumes are for Pay Per Click marketers. When they bid on keywords, their ads will also show for all close variants. So it makes sense that they see the merged search volumes when setting up campaigns.

In SEO however, each close variant keyword will show different SERPs. Thus it would be useful to have the ‘exact match’ search volumes for each term.

Lucky us. Why? Because KWFinder provides this exact data. This way, we were able to check the quality of the suggestions from different tools. We simply ran them through KWFinder to standardize and compare their search volumes.

To avoid inflated numbers, we made sure to clean all cases when we still suspected combined data. We simply took any merged volumes that showed up more than once out of the equation.

On top, we decided not to count the search volume of keywords with typos. Unlike for paid ads, it doesn’t make sense to optimize for typos since, usually, you end up with the same SERP anyway due to Google Autocorrect.

For us, it’s not surprising that the big players want to be independent of these kinds of shenanigans. Moz and Ahrefs rather calculate their data independently. They claim to take Google’s numbers as a basis only to improve it with third-party clickstream data from providers like Jumpshot.

But that’s already getting deep into the statistics jungle. So we’ll leave it at that for now.

If you’re keen on decoding the topic even further, look at this article for more insights on how to set up Google’s API. And guess what – even on Reddit you can learn more about keyword research. In this post, the team members from different tools joined a discussion about data accuracy.

For everybody else, it’s time to meet the contenders of our little contest!

Competing Keyword Research Tools

Introduction to Competitors

Here we go: The playing field is leveled.

Now we have an idea of what goes on behind the scenes of each tool and a standardized way to compare the performance.

Time to introduce the players themselves!

In this study, we compare five paid keyword research tools as well as one combination of free tools.

Like we mentioned before: We focus on keyword outputs. Many of the tools have a wide-range of other functionalities. If you want a full review of those, don’t forget to check out Authority Hacker!


First up is SEMrush, a tool that we’ve already been working with for a while in the past. Now it was time to ask the question:

Is it worth the subscription when comparing the outputs with other tools?

SEMrush works with national databases, so results are on a country-specific level.

According to them, their keywords are publically available (first 100 Google search results). Also they say to collect the data similarly to Google Keyword Planner.

We got in touch with them about where the data for their search volumes comes from. The final answer that we got was sadly vague. But we were positively surprised by the fast correspondence back and forth with the SEMrush team:

“The volume is also estimated using our algorithm. Sadly, this is as much as I can reveal :)”

High volume keywords get a more frequent (daily) update than low volume keywords (monthly). Further, they admit lacking local keywords since they collect data on a national level.

Since SEMrush works with national databases, you can only search on a country level. Besides, you can select between desktop and mobile databases.

One main metric in our case study is search volume. SEMrush defines it like this:

“Volume”: “The average number of times users have searched for a given keyword per month. We calculate this value over the last 12 months.”

What options does SEMrush offer for your keyword research?

It actually gives you three reports for traditional keyword research:

(1) Phrase Match Report, (2) Related Keywords Report, (3) Keyword Magic Tool. (Update: The three tools have been consolidated within the Keyword Magic Tool).

We used them all and removed any overlapping keywords.

You can also do competitive keyword research. With the Organic URL Research of SEMrush, you’re extracting keywords that your competitors rank for.


SECockpit was our second tool choice before starting this comparison.

It’s cloud-based and scrapes its data live from several sources, including e.g. Amazon or Youtube. It claims that it does so faster than other tools and with a better keyword difficulty score. Take a look at the developer’s comment to this post for some insights.

Unlike SEMrush, SECockpit has no own databases. They scrape all data live from APIs like from Google AdWords. Differences in the numbers with e.g. Google Keyword Planner can occur since the data is cached for 30 days.

SECockpit prides itself on delivering unique metrics for all sorts of SEO strategies. It’s true that you can choose from an immense list of metrics.

One thing that’s highly important for us, is the option to look for those metrics on an aggregated global level. This is only possible with half of the tools in that we were looking into. SECockpit is one of them.

Their definition of search volume also is straightforward:

“Monthly Searches”: “Monthly Searches based on the data from Google Keyword Planner.”

What options does SECockpit offer for your keyword research?

You basically get two types of keyword reports:

A traditional (1) “Keyword Phrase” report based on a Seed Keyword. And a (2) ”Website” report where you can scrape keywords from (your competitors’) URLs.

Your results can always be easily extended via the “expand list option”.

When conducting the competitive analysis for the SERP top 10 it took us quite a while, around 30 minutes. So it goes without saying that SECockpit doesn’t operate at the warp speed that it advertises with.


KWFinder is one of the newer players on the market and convinces with its simplicity. It has a well-arranged user interface that shows the most important metrics in one go.

It clearly has the potential to play in the big leagues soon if it keeps going at the same pace.

KWFinder uses the Google AdWords API and claims to display precise search volumes. Without merging close variants. It definitely is a smooth alternative to Google Keyword Planner.

KWFinder strikes the perfect balance for us:

Exactly the right settings we need with no information overload.

You can search on a global level and will get a nice overview of metrics as well as a SERP analysis – all on one screen. Their definition of search volume is:

“Search”: “Average monthly search volume (exact match) in the last 12 months.”