6 professional Google SEO keyword research tools


There are too many keyword research tools in the market, and people often ask me “Which keyword tool is good? Which keyword tools do you use often?” This article will introduce 6 professional keyword research tools and mention Some other auxiliary keyword tools. The keyword tools and data metrics for this article are provided by Authority Hacker and published on the Ahrefs blog.

Here are the best keyword research tools:

  1. Ahrefs Keywords Explorer (23/25 points)
    2. KWFinder (20/25 points)
    3. Moz Keyword Explorer (14/25 points)
    4. SEMRush Keyword Magic Tool (13/25 points)
    5. Long Tail Pro (12 /25 points)
    6. SERPStat Keyword Research Tool (10/25 points)

Keyword tool criteria, methods and results

Based on the experience of Authority Hacker, he believes that the perfect keyword research tool relies on five main criteria, namely:

  1. Keyword suggestions: Youmust find/recommended as many relevant keywords as possible.
  2. Data filtering: Youmust be able to easily filter large keyword lists.
  3. Search volume trend:The search trend for keywords must be displayed.
  4. Keyword difficulty:Must have a reliable keyword difficulty score.
  5. SERP analysis:Must have SERP analysis capabilities.

Authority Hacker will test six large keyword research tools for all of these criteria and then assign 1-5 levels to each standard. This will result in a total score of 25 points for each tool. (Niufeng thinks these five indicators are very reasonable and worth learning.)

Note: In order to test the “keyword suggestion” standard, the author used the word “massage” to compare the results of six tools.

1. Ahrefs Keywords Explorer (23/25 points)

Number of keyword suggestions: 5/5

Suggestion: 892,576 keywords

Ahrefs extracted the maximum number of keyword suggestions and was much higher than all other tools. Ahrefs’ keyword generator is driven by clickstream data and updates its database every month with new keywords.

Data filtering: 4/5

Ahrefs allows you to filter the entire list of keyword suggestions by search volume and keyword difficulty. Both of these metrics are cached and are always available for the entire keyword database.
This tool also provides some unique keyword metrics (and filters) for keyword suggestion lists not found in other tools, such as:

  • Click
  • Every search click
  • response rate

But it will only be displayed after clicking the “Get metrics” button.

Search volume trend: 4/5

This tool not only displays search volume trends starting in September 2015, but is further broken down based on whether the search caused actual clicks.
The search volume trend graph is visual and does not display search volume figures for the past few months.

Keyword difficulty: 5/5

The keyword difficulty calculation in the Ahrefs Keywords Explorer is based entirely on the backlinks of the top 10 pages in the SERP (no other metrics).

SERP analysis: 5/5

A very detailed SERP analysis. Ahrefs will show you the exact number of backlinks for your search results. It’s the only tool that shows the search traffic from the top-ranked pages (from all of their ranked keywords, not just your target keywords).

2. KWFinder (20/25 points)

Number of keyword suggestions: 2/5

Suggestion: 954 keywords

The tool has three types of keyword ideas: suggestions, autocomplete, and questions.
Note: KWFinder offers 200 or 700 keyword suggestions based on your membership package.

Data filtering: 4/5

Filtering with KWFinder is a breeze. There is only one drawback: keyword difficulty data is not immediately used for each keyword unless it has been previously requested by any user (unlike Ahrefs’s Keywords Explorer, which shows the keyword difficulty recommended by all keywords).

Search volume trend: 5/5

The search volume trend is well laid out in KWFinder style and contains all the data you expect.

Keyword difficulty: 5/5

They calculate based on the SEO statistics on the page on the Google homepage (DA, PA, MR, MT extracted from MOZ). In my experience, KWFinder’s SEO difficulty indicators are surprisingly accurate.

SERP analysis: 4/5

KWFinder’s SERP analysis is very simple and easy to understand. However, they are using backlink data from MOZ, which is not a perfect source of information. Maybe they should consider switching to the Majestic API.

3. Moz Keyword Explorer (14/25 points)

Number of keyword suggestions: 2/5

Suggestion: 1,000 keywords

Note: Moz has 1,000 keyword suggestion limits for any seed keyword.

Data filtering: 5/5

Although the filtering options in the MOZ tool feel somewhat limited, they provide unique semantic filters and grouping.

Search volume trend: 0/5

No Search Volume Trends data is available.

Keyword difficulty: 5/5

Moz uses the PA and DA metrics of the top ten pages of his keywords to calculate keyword difficulty. I must say that their difficulty score is very good.

SERP analysis: 2/5

Moz only provides the minimum data for the top 10 search results, such as the number of PAs, DAs, and reference domains.

4. SEMrush Keyword Magic Tool (13/25 points)

Number of keyword suggestions: 4/5

Suggestion: 440,273 keywords

Considering the excellent results of this tool (Keyword Magic) is still in the testing stage. However, this is only 40% of the number of Ahrefs recommendations.

Data filtering: 4/5

SEMrush meets all the expectations of the data you want to filter. Not bad at all.

Search volume trend: 3/5

A good standard trend chart covering the past 12 months. Instead of displaying search volume numbers for the past few months, it gives decimal scores, one of which represents the month with the highest search volume.
Note: To see search volume trends, you must leave the Keyword Magic tool and go to the Keyword Analytics -> Overview section

Keyword difficulty: 1/5

As explained in their knowledge base, SEMrush takes into account the permissions of the fields displayed on the results page to determine the difficulty of the keywords.
In most cases, their KD scores are completely wrong (based on our experience). In my opinion, this may be one of the biggest weaknesses of SEMrush as a keyword research tool.

Note: The SEMrush team discussed their keyword difficulty. They acknowledged this problem and are redeveloping it later.

SERP analysis: 1/5

SEMrush simply displays a Google SERP for a given keyword cached, with no data on the ranking page.

5. Long Tail Pro (12/25 points)

Number of keyword suggestions: 2/5

Suggestion: 893 keywords

A reasonable number of suggestions, but due to the “maximum results per seed keyword” limit, I had to run their “Google AdWords Suggestions” report multiple times.

Data filtering: 3/5

Quite a lot of filtering opportunities, but the interface may need some improvement.

Search volume trend: 0/5

No Search Volume Trends data is available.

Keyword difficulty: 4/5

Keywords The competitiveness of this tool is calculated using the page title, Majestic Trust Flow and Citation Flow, links and other factors found in the top 10 results on Google. In our keyword difficulty test, the keyword difficulty score from Long Tail Pro is the second most accurate score after Ahrefs.

SERP analysis: 3/5

A lot of reliable data. The downside of their SERP analysis is that it forces you to enter a new browser tab.

6. SERPStat Keyword Research Tool (10/25 points)

Number of keyword suggestions: 3/5

Suggestion: 149,003 keywords

Serpstat offers a lot of keyword suggestions. About 35% of SEMrush.

Data filtering: 2/5

Provide some good filtering options. However, you can’t filter or sort the list of suggestions by keyword difficulty.

Search volume trend: 3/5

Take advantage of the power of Google Trends embedding. However, it does give you a comprehensive picture of the keywords that search for words that change over time.

Keyword difficulty:?/ 5

Serpstat estimates its keyword difficulty based on a number of factors, such as the backlink profile for the top 10 search results, page rank and trust level, and page factors such as keywords in the title and URL.
The indicator was added to Serpstat in June 2017 and was not tested by the author.

About the standard explanation used above

Number of keyword suggestions

Usually, the keyword tool gives you more keywords, and the more likely you are to find a good opportunity. The only fair way to compare keyword tools is to run the same query word through each tool and record the results.
These tools use the keyword “massage”. The keyword suggestion count was taken on November 17, 2017. Since these keyword tools update their databases on a regular basis, it may be slightly different if you perform similar tests today.

Data filtering

A list of keyword suggestions is just the beginning of keyword research. In addition, you need to effectively filter this list. A good keyword tool must provide simple filtering options, regardless of which other keyword metrics these tools have, search volume and keyword difficulty are required.

Search volume trend

Now, after filtering out the list of keyword suggestions, you have some good keywords, and you need to do a separate keyword analysis. Over time, keyword search volume trends are essential to see if the searcher’s interest is rising or falling, and whether seasonality will affect it.

Keyword difficulty

Every good keyword research tool has some form of difficulty or competitive score (don’t confuse it with “competition” in GKP, which only applies to advertising). This metric must show the difficulty of ranking for any given keyword. With it, you can easily filter a large number of keyword suggestions and find suggestions that are easy to rank. Ahrefs gets 5/5, not only because it is the author’s personal favorite SEO tool.

If you still think that the author is only biased towards Ahrefs, then another keyword difficulty study by Kelvin Mah of Humanproofdesigns: Which keyword difficulty checker is the most accurate? Ahrefs also won there.

SERP analysis

Keyword difficulty can help you narrow down the list of keyword suggestions. But it does not replace the manual review of the SERP. That’s why a good keyword tool should not only give you a fairly reliable keyword difficulty score, but once you identify a potential good keyword, it will give you enough data.

Why this article doesn’t include Google Keyword Planner (and some other keyword research tools)

You may have noticed that the Keyword Tool test did not include Google Keyword Planner. This is because GKP is a special tool for PPC advertisers and does not fully assist in SEO keyword research. Google Keyword Planner has one of the biggest effects on SEO, which is that it can display the search volume of keywords. You can use the google keyword planner and the above tools to conduct SEO keyword research.

But in addition to GKP, you may be wondering why you don’t include some other famous keyword research tools, such as:

  • Ubersuggest

Because these keyword tools can not reach the professional level, that is to say, the number of keyword suggestions, data filtering, search volume trend, keyword difficulty, SERP analysis can not be achieved.


You saw the results of this article test. However, there are more things to consider when choosing a keyword research tool. All in all, your choice must depend on your level of SEO knowledge and the work you want to do. Ahrefs is an experienced SEO tool that uses this tool to get every detail, and KWfinder is the perfect choice for a new SEO, because its price is very cheap and cost-effective. Of course, you can also go to a treasure to buy a shared version of Ahrefs.


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