It gives you instant access to the following Page and Domain metrics:
Domain Rating (DR);
URL Rating (UR);
Estimated Organic Search Traffic (ST);
Number of ranking keywords (KW);
Number of referring domains (RD);
Number of backlinks (BL).
Besides, you can see all of these metrics right below every page ranking for the keyword you're searching for.
In addition to this, Ahrefs SEO Toolbar will show you the most important keyword metrics right on the SERP:
Search volume (both Global and Country-specific);
Keyword Difficulty (KD);
Cost per Click (CPC).
Installing the Toolbar
Installing the toolbar is easy.
For Chrome users, head to this link and install it.
For Firefox users, head to this link and install it.
Using the Toolbar
Ahrefs SEO Toolbar provides a bunch of free features. However, you need an active paid account at ahrefs.com to get SEO metrics.
For the new pricing plans (introduced after 18 March, 2022)
Using the SEO toolbar does not consume reports.
The usage is limited by the internal anti-fraud system to prevent data scraping. But you will have enough credits for the normal usage.
For the legacy pricing plans (purchased before 18 March, 2022)
The Toolbar consumes one Site Explorer “Rows per month” credit to show page and domain metrics for the URL that you visit. SEO metrics for each search displayed on SERP also consume one credit.
Keyword metrics shown under the search bar consume one “Rows per month” credit from the Keywords Explorer limits.
No credits will be spent if the metrics display is disabled in the Toolbar settings.
What features are free?
Even if you don't have a paid subscription, Ahrefs SEO Toolbar provides a lot of tools and reports for free:
On-page SEO report including details about page titles, descriptions, canonicals, hreflangs, sub-headers, crawl-ability/index-ability, social tags, etc. is free. (the Content and Indexability tabs)
Outgoing link checker
Redirect tracer and HTTP headers reader
Location changer for SERP