There are a number of bibliometric indicators focusing on measuring impact of scholarly journals.  Most of these measures are calculated from the pool of journals indexed in two citation indexing databases: Web of Science or Scopus.

Journal Impact Factor
Journal Impact Factor (or JIF) is the most commonly-used metric used to indicate journal quality. JIF is a 2-year calculation based on the total number of citations to articles published in the journal.

All metrics based on Web of Science-indexed journals can be access via:

Tips for tracking citations to published works:

Google Scholar 

• Includes multi-disciplinary journal articles, conference proceedings, and books. 

• Search for a particular work, then click on Cited by (number). 

Web of Science

• Includes journal articles (in Science Citation Index, Social Science Citation Index, and Arts & Humanities Index databases),

• Use Cited Reference Search to see how many times a particular work or author has been cited.

• Or, search for a particular work, then click on the number that follows Times Cited. 

• Create a Citation Alert to be notified of when a particular work is cited.

ScienceDirect 

• Includes journal articles in medicine, science, some social sciences, and some humanities. 

• Search for a particular article, then click on Citing Articles (number). 

Inciteful

• Uses available research metrics and network analysis algorithms (AI) to construct a large network of papers around a paper of your choice.
• You can find the most similar papers, important papers as well as prolific authors and institutions.

Author-level metrics are citation metrics that measure the bibliometric impact of individual authors. H-index is the best known author-level metric (proposed by JE Hirsch in 2005). The h-index (AKA Hirsch index) is a combined measure of both productivity and impact. An index of h means that your h most highly-cited articles have at least h citations each.

The h-index is more informative than total number of articles (which ignores how well those articles have been received by other researchers) or total number of citations (which can be inordinately influenced by a small number of highly-cited articles and therefore not an accurate reflection of productivity). 

One caveat about the h-index is that it correlates with the length of a researcher's career (i.e., researchers who have been publishing for longer tend to have higher h-indices). It can also be inflated by self-citation. In addition, the h-index ignores the order of authorship, which is very important in some disciplines. Additionally, because different disciplines have different publishing practices, the h-index should not be used to compare researchers across different disciplines. Average impact scores vary widely from discipline to discipline.