What are traditionally referred to as "official" impact factors, this metric is calculated using citation data for the purposes of evaluating the impact and use of scholarly journals in the sciences and social sciences via the InCites Journal Citation Reports platform. Impact Factors are assigned solely by Clarivate Analytics and are only available for the journals listed in:
Scimago's SJR (Scientific Journal & Country Rank) is an alternative to the traditional impact factor that draws journal data from Elsevier's Scopus database and ranks the data according to the rankings and other metrics, including the h-index, total citations, and total documents. Data is available from about 20,000 journals in the sciences, social sciences, and humanities. Access is available via:
CiteScore is a journal level metric from Elsevier/Scopus that calculates the number of citations received by a journal over the past four years divided by the total number of articles published over those four years. Complimentary access is available from the Scopus Sources preview website and is applied to over 22,000 citations.
SNIP: Source Normalized Impact per Paper
This is the ratio of citation count per paper for the journals indexed in Scopus. This metric can be accessed from an open source database provided by the Centre for Science and Technology Studies (CWTS) at Leiden University, The Netherlands.
Google Scholar Journal Metrics
From the Google Scholar menu, choose Metrics. From the default list of Top publications, you can then choose Categories and then Subcategories to see the top 100 journals listed by h5-index and h5-median (H5-index -- The largest number h such that h articles published in the past 5 years have at least h citations each. So an H5-index of 44 means that the journal has published 44 articles in the previous 5 years that have 44 or more citations each. H5-median provides the median number of the H-5 index citation values)
Harzing.com provides an annual Journal Quality List for a select group of social science and business journals, plus a downloadable "Publish or Perish" program to provide citation metrics from Google Scholar.