Skip to Main Content

Web of Science: Journal Impact Factor

What is Journal Impact Factor?

The Journal Impact Factor  was developed in the 1950s1 and is a widely-used measure of the influence of journals. Impact Factor is calculated and published annually by Clarivate in the InCites Journal Citation Reports database. It covers over 9,500 science journals, 3,500 social science journals, 1,700 arts and humanities journals, and 4,600 gold open access journals. The Journal Impact Factor is based on citation data from the Web of Science and reflects the annual average number of citations a given journal receives. It uses the formula:

2020 Journal Impact Factor equals Cites in 2020 to articles published in Journal X in 2018 and 2019 divided by the Total number of articles published in Journal X in 2018 and 2019

The resulting number represents the average number of citations to an average recent article in the journal. Note that not all journals have an Impact Factor since Impact Factor can only be calculated for journals included in Web of Science.

Limitations of Journal Impact Factor

While Journal Impact Factor can be a useful metric for assessing the relative "importance" of a journal, there are some limitations to keep in mind:

  • Citation and publication practices differ depending on discipline, so Journal Impact Factor should not be used to compare journals across disciplines.
  • Impact Factor does not assess the quality of individual articles.
  • Not all journals have an Impact Factor. They must be indexed in JCR, which only indexes a subset of Web of Science journals.

Finding Journal Impact Factor in Web of Science

To view a journal's impact factor in Web of Science, click on the journal name link in a given reference.

Screenshot pointing out journal name in a Web of Science citation page, which allows you to view a journal's impact factor

The resulting pop-up gives a summary of information from Journal Citation Reports, including the most recent Journal Impact Factor score and five year average.

Screenshot showing journal citation report detailed pop up

Journal Citation Reports

Journal Citation Reports (JCR) can also be searched independently. Access JCR by following the link in the Products dropdown menu on Web of Science or by searching for Journal Citation Reports on the library's A-Z Databases page.

Screenshot pointing out Journal Citation Reports link from product dropdown at the top right corner of Web of Science's homepage

Entering Journal Citation Reports directly allows you to produce lists of journals by subject, and to rank journals by Impact Factor and other measures. You can use this information to help you decide which journals to find research or publish in.

To find a journal in JCR, search by journal name, ISSN, category, or keyword and select from the dropdown. You can also browse journals and categories using the links at the top of the homepage.

Screenshot showing the Journal Citations Report homepage, searching BMC Bioinformatics

Every journal in JCR has a journal profile page, showing information pertaining to journal category, performance, and bibliographic data.

Screenshot showing the journal profile page for BMC Bioinformatics in Journal Citation Reports

Scroll down on the journal profile page to view journal performance indicators, including Journal Impact Factor.