Compares and evaluates 7500+ journals in the sciences, technology, health sciences and social sciences and calculates their Impact Factor, Eigenfactor, and field-based journal rankings.
Various criticisms have been raised about impact factor, including its validity (it is highly discipline-dependent) and the effect that journal editorial policies can have on it (policies can potentially boost a journal's impact factor).
SCImago is a free Web site that runs on Scopus data to calculate two metrics: SCImago Journal Rank (SJR), which indicates the influence of the average article from the journal and Source Normalized Impact per Paper (SNIP), which compare directly to Web of Knowledge’s Impact Factor. SJR is based on times cited, but also uses an algorithm similar to Google’s PageRank to calculate article influence, which it uses to create rankings; it accounts for both the number of citations received by a journal and the prestige of the journals where such citations originated. Users can compare rankings of up to ten journals at a time and display top journals.
Uses Scopus citations only from 1996-present. Divides the prestige gained by a journal, through the citations of its articles, to the total number of articles included, rather than to the number of citable articles.
UW-Libraries have created a guide detailing methods you can use to easily keep up with the literature in your field: Keeping Current Guide