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Ahrefs SEO metrics

Keyword and Search Traffic Metrics

Video for this tutorial is coming soon.

Ahrefs has an extensive keyword database of 28,9 billion keywords (and the largest US keyword database: 5 billion keywords), covering 226 geographic regions – the most covered by any SEO tool.

In this lesson, we’re covering:

  • Search volume
  • Total number of keywords
  • Organic traffic
  • Traffic value
  • Top keyword
  • Keyword Difficulty
  • Traffic potential
  • Parent topic

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Search volume

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Search volume represents the average number of times people search for a query in a target country in a given month.

We use Google Keyword Planner data as a base to build our model, which is the data that you see in every other third party keyword tool.

At this time, search volume in Ahrefs is calculated based on a 12-month average.


You can change the search volume graph period from: last year, to last two years, to all time. This should help you visualize trends much more easily.

Keyword Trend

Total number of keywords

This metric is calculated by counting all search queries a URL, subfolder, or domain ranks for in the top 100 search results.

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For example, if I search for “how to lose weight,” Healthline’s article appears at the top of Google. That’s one keyword. But they also rank for “how to lose weight fast,” “weight loss,” and over 6,000 keywords in the US alone.

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Our keyword rankings are grouped by country since search results will usually differ based on location and Google ccTLD.

Organic traffic

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This metric is an estimation of how much organic search traffic your target website, subfolder or URL gets each month.

How it’s calculated:

  1. We find all the keywords for which your target ranks in the top 100 organic search results
  2. We estimate the search traffic your target gets from each of those keywords based on its ranking position, monthly search volume and our estimated CTR for that position
  3. We sum up the traffic estimations of each keyword.

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Treat the organic traffic estimations in Ahrefs as precisely that: estimations. Here’s why.

  • We don’t know all possible search queries a page ranks for. On a daily basis, 15% or around 500 million searches have never been seen before by Google's search engine.
  • Search volumes are just approximations. Even Google doesn’t give exact values.
  • Ranking positions are volatile and can change by the second.
  • Our CTR estimations are also approximations based on our own CTR model.

These four things contribute to discrepancies in search traffic estimations for our tools as well as any other tool providing a similar metric.

However, these estimates work well for learning whether competitors’ websites get more or less organic search traffic compared to yours.

You can use the following formula to estimate your competitor's traffic:

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Traffic value

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Traffic value shows the value of the organic search traffic, if it were to be acquired via PPC in Google Ads.

To calculate it, we take the estimated search traffic for a keyword and multiply it by the CPC value for that keyword. Then we sum the total values to come up with a total traffic value metric.

For example, let’s say that a page ranks for 2 keywords: blue widgets and red widgets.

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Blue widgets is responsible for sending the page 100 monthly organic visits and has an average CPC of $2. The traffic value for that keyword would then be $200. On the other hand, the keyword red widgets is also responsible for generating 100 monthly organic visits and has a CPC value of $1.

The traffic value for that keyword would be $100, and the total traffic value for that page would be $300.


The cost per click metrics are highly volatile and can change by the second.

Regardless of exact live values, this metric can be helpful to understand the commercial value of both yours and your competitors’ pages so you can prioritize your SEO and marketing tasks accordingly.

Top keyword

This is the query that brings the most search traffic to a URL. We select the top keyword by looking at all the keywords a target ranks for, then choosing the one with the highest organic traffic estimation.

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Keyword Difficulty

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Keyword Difficulty estimates how hard it’ll be to rank in the top 10 organic search results in a specific location.

It’s essentially a proxy to link popularity of the top 10 search results.

We calculate Keyword Difficulty (KD) from the number of backlinks to the top-ranking pages. by taking a weighted average of the number of linking domains to the top-ranking pages. We remove certain outliers to better represent ranking difficulty. Then, the value of the calculation is plotted on a logarithmic scale from 0-100.


Keyword difficulty doesn't take anything else into account. You should always study the top 10 results manually for a more complete sense of ranking difficulty.

Traffic potential

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Traffic potential shows the sum of organic traffic that the #1 ranking page for your target keyword receives from all the keywords that it ranks for.

This is a much better metric than search volume alone, as it reflects the total traffic sent to a page and not the total number of searches for a topic.

For example, the keyword “submit website to search engines” has a traffic potential of 6.4k, even though it only has a search volume of 500.

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Parent topic

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Parent Topic determines if you can rank for your target keyword while targeting a more general topic instead.

To identify the Parent Topic, we take the #1 ranking page for your keyword and find the query responsible for sending the most search traffic to that page.

For example, let’s say you own a fitness site and you want to teach people how to do lunges with weights. If you analyze the query “how to do lunges with weights," you’ll see that the search volume is 350. However, the Parent Topic is “lunge with weights.”

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It looks like the #1 result for this query gets an estimated 2,000 monthly search visits.

Next lesson

Navigating Ahrefs