SEMRush and Moz Link Indexes Compared

Historically, Moz has internally tracked comparisons with both Ahrefs and Majestic on a daily basis to ensure our Link Explorer product is a market leader. However, I have received several requests recently to compare Moz to SEMRush given their strides in growing a link index of their own. Below are the results of a simple study comparing index size based on the following metrics:

1. Overall reported backlinks (Self Reported)
2. Likelihood Moz or SEMRush reports more referring domains to a domain (Sample Size: 1000 domains)
3. Likelihood Moz or SEMRush reports more backlinks to a domain (Sample Size: 1000 domains)
4. Likelihood Moz or SEMRush reports more referring domains to a URL (Sample Size: 1000 URLs)
5. Likelihood Moz or SEMRush reports more backlinks to a URL (Sample Size: 1000 URLs)

These are simple size metrics and not as comprehensive as our primary internal metrics which are described in detail in one of our initial launch posts. Nevertheless, this should give readers an idea of the scope of Moz’s Link Explorer compared to SEMRush’s link index.

Overall reported backlinks

Likelihood Moz or SEMRush reports more referring domains to a domain

Likelihood Moz or SEMRush reports more backlinks to a domain

Likelihood Moz or SEMRush reports more referring domains to a URL

Likelihood Moz or SEMRush reports more backlinks to a URL

Conclusions

While SEMRush’s index has grown in size, it still remains well behind the “big 3” (Moz, Majestic and Ahrefs).

I will make one quick retraction. I can’t say with certainty that they remain “well behind the big 3”. Rather, all I can say given this research is they remain well behind Moz. 

I will take a look at their index again in a few months and see if it warrants including in our standard daily internal tracking, but as of the moment it is not in contention.