You can search for journal rankings in large, subject specific databases. Web of Science, owned by Clarivate, publishes the Journal Citation Report, a respected subscription service publishing journal rankings in the sciences.
The UML Library does not subscribe to Web of Science, but a bit of web searching reveals links to their lists of Journal Impact Factors published in Journal Citation Reports. Also, the libraries of the Boston Consortium offer Web of Science access to UML researchers, but you have to go in person.
To get a Boston Library Consortium card go to the circulation desk at either O'Leary or Lydon Libraries.
Google Journal Metrics
Start at Google Scholar and click the Metrics tab, (aka. hamburger, menu icon), upper left of page.
A way for authors to quickly gauge the visibility and influence of recent articles in scholarly publications. Scholar Metrics summarize recent citations to many publications, to help authors as they consider where to publish their new research.
UML Library subscribes to Dimensions, a linked research data platform, similar to PubMed, Scopus, or Web of Science. Dimensions is designed to provide knowledge about what is going on in your research area, and how this is changing over time.
Dimensions does not include journal impact factors, but instead uses article-level metrics. Publication citations' refers to the number of times that a publication has been cited by other publications in the Dimensions database.