Keyword research is the foundation of almost every successful digital marketing campaign. No matter if you prepare an SEO, PPC, or content marketing campaign you need to start with one thing – keyword research. And no matter if you work as an SEO consultant, PPC expert, or Content marketer, you need to master the keyword research technique.
Fortunately, there are dozens of great keyword research tools that simplify this task for you and the good news is that many of them are FREE!
In this article, I will present my favorite tools for keyword research as well as their pros and cons.
1. Google keyword planner
I start with Google Keyword planner not because I believe it’s the best free tool but because it’s considered the alpha and omega of keyword research.
It’s provided by Google, as part of the Google AdWords platform, it’s completely free and it’s easy to use.
Best for: to examine search volume and find keyword ideas
The Keyword Planner is most widely used to search for new keywords and find out estimated search volume data. For the purpose of this article, let’s say I have a website that sells peanut butter products and I use GKP to do keyword research:


The Keyword Planner will generate a long list of keywords (called keyword suggestions, or keyword ideas), based on the search terms that you’ve initially entered in the tool (in my case it’s “peanut butter”). Your job is to assess the value of each keyword suggestions and decide which ones you should use on your website.
For example, for my peanut butter websites, I’ve found the following keywords: “natural peanut butter”, “organic peanut butter”, “crunchy peanut butter”, “creamy peanut butter”. I also found some keywords I could use on my blog: “peanut butter recipes” and “peanut butter nutrition”.
Google Keyword planner is also very useful for analysis of local search volume data, as it allows filtering statistics and traffic estimates per language and location.
Pros: It’s completely free! The data is provided by Google. Very useful for local SEO.
Because of its fine targeting options, it is a valuable resource for local, service-based businesses that need to perform keyword research for a specific area (for example SEO consultant Hong Kong)
The tool allows you to filter keyword data by language and by location.

Cons: Can’t be used to estimate keyword difficulty. No way to filter keywords by keyword groups or semantic fields. Not useful for highly seasonal products. Can’t filter keyword search volume by device … Ok, I stop
Can’t be used to estimate keyword’s difficulty: For me, the biggest downside of Google Keyword Planner is that it doesn’t give you any information about the Keyword Difficulty and your Ranking Probability. The tool will help you to find a lot of keyword suggestions, but you don’t know how difficult it would be to actually rank for these keywords.
Not good to understand search trends: Google Keyword planner is not very good at presenting search trends also. The keyword search volume that you see is, in fact, the “average monthly searches” data. It is calculated from the search volume over the past 12 months.
This can be misleading for people who are not experienced with the tool and the “average monthly searches” data is useless when you do keyword research for highly seasonal products.
You can, however, mouse over the graph icon to the left of each keyword to get a snapshot of the last 12 months or use the date range filter to review search volume per month.
Doesn’t have advanced filtering options: Another downside of GKP is the lack of filters.
The tool will give you many keyword suggestions (in my case I had 700 keyword suggestions for “peanut butter”) but many of them are not relevant or very remote from the lexical and semantic field of the seed keyword.
Requires Google AdWords account: To use the tool you are required to set up a Google AdWords account (but you can use the tool even if you’re not running Adwords campaigns).
Mobile vs. Desktop Traffic: Another downside of the tool is that you’re not able to filter keyword search volume by the device (mobile vs.desktop).
2. Ubersuggest
Ubersuggests has been around for a while now, but for some reason, I feel that it’s not so popular and used as it should be. It is a great tool and also completely FREE!
Best for: to find long-tail keyword ideas.
Ubersuggest is perfect to expand on a base keyword and to find long-tail variations of your main keywords. It’s also perfect to find topics to write about in your articles.
Pros: It’s completely free! Pulls data from Google Suggest. Super simple to use.
This keyword research tool pulls data from Google suggest, therefore I can say it’s completely reliable.
Moreover, it is very easy to use and the interface is not complicated at all!
Here are the keywords that Ubersuggests suggested for “peanut butter”:


Although the number of suggestions is lower than the one from GKP, I was able to find at least 10 keywords that weren’t listed by GKP. The research also took me less time.
Cons: No search volume data. No advanced features. No way to assess keyword difficulty and competition.
Unfortunately, Ubersuggestsdoes not have any of the advanced targeting and filtering features that other keyword tools have.
It doesn’t show search volume data as Google Keyword planner does. For that reason, it is only useful to review alongside the other tools.
3. SEM Rush
Google’s Keyword Planner and UberSuggest are great tools, but to use them you need to build a list of sample keywords that you think are connected with your business. The keyword ideas that these tools generate are entirely based on this initial keyword list that you create.
But who knows your business better than you, right?
Well, your competitors may know it better than you! That’s where SEMRush comes!
Best for : competitive keyword analysis
SEM Rush is THE tool for competitive keyword analysis.
It helps you to find out what keywords your competitors are targeting and ranking for. Considering this way you can create better content and steel some of your competitors’ traffic!
Pros: Several SEO tools in one.Keyword difficulty score. Competitors’ keyword analysis. Location targeting.Keyword trends.
SEMRush is not only a keyword research tool, but it offers an entire SEO suite. You get a lot of useful functionalities with this tool including site auditing, keyword rankings, backlink analysis, SEO ideas, mentions monitoring, and others.
In this article, I only focus on the keyword analysis function.
In itself the keyword tool is great and it offers some advanced features that we won’t find in the Google Keyword planner. For example, let’s do a keyword research about “peanut butter” with SEMRush.

Besides the keyword ideas (that are separated in phrase match Keywords and related keywords) SEMRush shows you the keyword trend and can filter keyword data by device.
When you zoom into the phrase match or related keywords reports you will find more detailed data for each keyword: avg.search volume, keyword difficulty scores, number of pages that organically rank for this keyword, trend, and others.

The keyword difficulty score is one of the main metrics you need to look at here! It helps you to understand how difficult a keyword may be to rank for.
Another nice feature is the number of pages that rank for this keyword. The combination of these two metrics will give you a pretty good idea of your chances to actually rank for the keywords that you’ve identified.
But what I really like about SEMrush is how you can search up your competitors and get an idea of the keywords they’re ranking for along with their estimated organic search traffic.
SEM Rush allows you to enter our competitors landing pages to extract high volume relevant keywords.
For example, here’s how one of my peanut butter competitors is performing in organic search:

I can see an estimate of his organic and paid traffic, the distributions of his organic positions, his top organic and paid keywords (in this case, my competitor doesn’t have paid keywords).
And let’s have a look at the targeted keywords of another competitor website:

Apparently this competitor is targeting many keywords I would have never think of!
Cons: It’s a paid tool.
Besides the fact that SEM Rush is paid (and not cheap), I can think of anything else.
Some say that the user interface is not very clear, but once you get used to it, it’s really good!
4. MozKeyword Explorer
Here’s another keyword research tool that’s part of a bigger SEO toolset: the Moz Keyword Explorer is just one of the features in Moz Pro.
Best for: to find keyword ideas and assess keyword difficulty
Pros: Difficulty Score, Volume Score, Opportunity Score Google SERP.
Moz Keyword Explorer is similar to Google Keyword Planner: it generates a list of keyword suggestions based on a given query. But the value of this tool consists in the additional keyword metrics: Difficulty, Volume, and Opportunity scores.
The Difficulty Score is calculated based on the Page Authority (PA) and Domain Authority (DA) scores of the results ranking on the first page of Google’s search engine for the given query.
Volume Score: the tool also pulls its own search volume data, which MOZ says, has “over 95% accuracy”. According to their website, the volume score captures fluctuations in traffic due to market seasonality and other trending factors. Therefore the MOZ volume score is more accurate than the avg. search volume in Google Keyword Planner.
And probably the most valuable addition to this keyword tool is the Opportunity Score. Basically this metric measures SERP CTR and takes into account all the additional features seen in Google’s results pages (images, answer boxes, knowledge graphs, carousels, maps, etc.) that tend to impact the CTR of the organic search results.
Let’s try to find keyword ideas for “peanut butter” with Moz Keyword Explorer:

When I look for keyword suggestions with Moz Keyword Explorer I personally prefer to look at the CSV. extractions because there you can clearly see the min and max search volumes, as well as relevancy score.
In this case, the relevancy score saved me a lot of time because I only wanted to review the closest variations to my seed keyword (so I only checked the keyword suggestions with relevancy score 5, 4, and 3).
Another way to filter this data is by using the topic and keyword groups filters:


Cons: Paid. Not so good for competitors’ keyword analysis.
Unfortunately, Moz Keyword Explorer doesn`t calculate difficulty, volume and opportunity scores in the Keyword suggestions report.
Furthermore, the tool doesn’t analyze your competitors’ keywords.
Moz Keyword Explorer is paid, but you are allowed on 2 keyword queries per day for free.
5. KW Finder
A cheaper alternative to MOZ Keyword Explorer is KW Finder.
Best for: to find long-tail keyword ideas and asses real-time keyword difficulty
Pros: Cheap Price. Real-time SEO difficulty score. SEO competitiveness rank. Filters. Geo-targeting. Google SERP.
KW Finder is a paid tool, but its price is really accessible (12 USD/month). If you use a free account you are allowed to 5 KW lookups per data, but most of the keyword suggestions will be hidden.
Let’s take a look at the keywords KW Finder suggests for “peanut butter” :
What I really like here is the clear user Interface and the Geo-targeting options. You can narrow your keyword research to a region or even city level worldwide and in more than 40 languages.
KW Finder also calculates SEO competitiveness rank and SEO difficulty score per keyword.
The SEO difficulty of a keyword is based on the DA, PA, MozRank, MozTrust of the pages on the first Google SERP. Moreover, KW Finder calculates the keyword difficulty in real-time.
The SEO competition for a particular keyword is based on a comparison of the keyword difficulty of keywords on a market-wide basis.
Google SERP statistics are also a good addition to the tool, but they don’t add-up anything compared to the SERPs analysis that you will get from Moz Keyword Explorer. In fact, KW Finder uses most of the Moz metrics.
Cons: No competitors’ keyword analysis. No mobile vs. desktop data.
A big downside of the tool is that you’re not able to filter keyword search volume by mobile and desktop. And there`s no competitors keyword analysis.
We saw that most keyword research tool have their pros and cons. And while each of these 5 tools is very useful tools, they may serve different purposes.
That’s why, an experienced SEO expert should use a variety of keyword tools, in order to conduct more in-depth keyword research and to go above-and-beyond keyword suggestions.