This search engine optimization (SEO) guide answers the question, “how is Keyword Difficulty calculated?”
Below, you’ll find a detailed explanation of Keyword Difficulty is measured as well as an overview of what factors go into the final calculation.
There’s also a section with additional resources that explain more about the fundamentals of Keyword Difficulty to help you create the most effective SEO strategy for improving your website’s rankings in the search engine results pages (SERPs).
Table of Contents
How Is Keyword Difficulty Calculated?
Keyword Difficulty is calculated by measuring the number and quality of backlinks to the top 10 pages in the search engine results for a keyword. Calculations for the Keyword Difficulty metric are also based on SEO data such as Domain Authority, Page Authority, referring domains, and dofollow/nofollow link ratios.
Keyword Difficulty Calculation Explained
Keyword Difficulty is calculated by a score between 0 and 100. The lower the score on the scale, the easier the keyword is to rank. A score of 50 or greater indicates a higher keyword difficulty score. The API, or application programming interface, pulls the top-ranked web pages on Google based on the keyword.
All keyword research tools have their own proprietary way of calculating Keyword Difficulty for SEO. That’s why each tool reports a different Link Profile Strength or LPS for each ranking URL, which affects the final KD score. However, companies like DataForSEO that offer SEO metrics for the tools provided are transparent about how their software calculates Keyword Difficulty.
The calculation for finding the rank for Keyword Difficulty (KD) is computed as follows:
- The API software collects the top 10 pages based on the keyword.
- Based on the first domain, the ranking score is calculated for the keyword based on how many backlinks point to the page and domain.
- There is a separate ranking system for backlinks, which begins at 0 for no links to 1,000, the top ranking score.
- Both the domain rank and page rank are used in the calculation. The page rank is multiplied by 0.9, and the domain rank is multiplied by 0.1.
- This calculation is completed for each of the top 10 web pages and their domains.
- The API sorts the pages by these values, from lowest to highest, then calculates the median.
- 0.2 is subtracted from the median value, and the result is divided by 0.8, then multiplied by 100 to convert the number to an integer.
Note: The rank value of keywords and web pages significantly changes based on location, which means where you conduct the search, can influence the results due to local features and details that may be included. For example, a search in a specific region may cause certain keywords to rank higher than another country or region where the criteria are less relevant.
Measured Factors for Keyword Difficulty
Domain Authority
Domain Authority is an important metric that goes into the calculation for Keyword Difficulty. The KD algorithms measure the total number of backlinks pointing to each of the top-ranking domains and factor those numbers into the KD score.
If there are many websites in the top 10 search results with higher Domain Authority (DA) metrics for a target keyword phrase, then the KD score will be higher. Conversely, if multiple websites are ranking for a keyword that have low DA scores (an indicator of a lower number of total backlinks pointing to the entire domain), then the KD score will be calculated to be lower.
Page Authority
Page Authority factors into the KD calculation similarly to Domain Authority; however, Page Authority (PA) only measures Keyword Difficulty values on a page-level basis.
When multiple web pages with high PA scores rank within the top 10 URLs for a keyword, this results in a higher Keyword Difficulty score. Conversely, if many websites are ranking for a keyword that have low PA scores (an indicator of a lower number of total backlinks pointing to the individual URL), then the KD score will be calculated to be lower.
Referring Domains
Referring domains are the websites that are linked to a target site through backlinks. For example, if a website has a backlink from a single third-party site, then this is referred to as one referring domain.
Websites can have multiple backlinks from the same domain, such as a single page linking multiple times or different pages linking out to the same site repeatedly. However, the collective of all links from the same website is still considered to be a single referring domain.
Keyword Difficulty is measured by both the number and quality of referring domains linked to a website. When there are many sites with a high number of quality referring domains ranking for a keyword, it’s likely that the keyword will be difficult to rank for (i.e., has a high KD score) unless your web page can get an equal amount of referring domains to compete.
Dofollow and Nofollow Link Ratios
Dofollow and nofollow links are two types of links that are used on websites when linking out to other domains. The main difference between these types of links is that dofollow links always page PageRank value to the target website. Nofollow links, on the other hand, are a hint; not a directive. Therefore, the nofollow link may or may not be used for assessing PageRank calculations.
The link ratio between dofollow and nofollow links for the top-ranking URLs in the SERPS for a target keyword affects the Keyword Difficulty score. For example, if the top-ranking pages have an average link ratio of 60:40 with 60% dofollow links and 40% nofollow links, then it may be hard to compete against those pages if your web page only has a ratio of 10:90.
Essentially, the more dofollow links your web pages have, the better your chance is to rank higher in the SERPs. Additionally, the more dofollow links a group of websites in the top 10 positions on Google have for a specific keyword, the more difficult it will be to rank for that keyword and the Keyword Difficulty score will reflect that in the keyword research tool.
Learn More About Keyword Difficulty
The links below explain more about Keyword Difficulty and how to use it correctly for better search engine optimization. Use these resources to expand your knowledge on the subject.
- Why Is Keyword Difficulty Important In SEO?
- What Is a Good Keyword Difficulty Score In SEO?
- Best Keyword Difficulty Checker Tools for SEO
Keyword Difficulty Calculated & Measured In SEO Summary
I hope you enjoyed this guide answering the question about how is Keyword Difficulty calculated in SEO.
As you discovered, Keyword Difficulty is calculated by measuring the number and quality of backlinks to the top 10 pages in the search engine results for a keyword. Calculations for the Keyword Difficulty metric are also based on SEO data such as Domain Authority, Page Authority, referring domains, and dofollow/nofollow link ratios.
