Frontiers in Microbiology Impact Factor

The Frontiers in Microbiology impact factor is the Journal Impact Factor associated with that journal: citations in a given JCR year to items published in the previous two years, divided by the citable items from those two years. The journal page showed 5.8 on 8 November 2026 without a data-year label.

ByCASRAI Editorial Board

· Last updated 8 Nov 2026

Frontiers in Microbiology Impact Factor

Frontiers in Microbiology is a journal published by Frontiers. Its journal page lists indexing in Web of Science (Science Citation Index Expanded), Scopus and PubMed Central, and shows the two figures above next to its citation count. The page does not describe either figure further, so the only claims that can be made from it are the displayed values and the date they were read. Impact factors are year-specific: a number quoted without its JCR year cannot be compared with another journal’s.

For the journal’s scope and editorial model, see the CASRAI guide to Frontiers in Microbiology.

How the impact factor is calculated

Clarivate defines the Journal Impact Factor as a ratio. The numerator is the number of citations received in the JCR year by items the journal published in the previous two years. The denominator is the number of citable items the journal published in those two years. Clarivate also describes a five-year impact figure computed over a longer window.

In symbols, for JCR year Y: JIF_Y = C_Y / N_{Y-1, Y-2}, where C_Y is the count of citations in year Y to items from years Y-1 and Y-2, and N is the count of citable items from those two years. A value of 5.8 therefore means that, on average, each citable item in the two-year window was cited 5.8 times in the data year. It is an average over a skewed distribution, not a typical article’s count.

Impact Factor versus CiteScore

The Frontiers page shows both an Impact Factor (5.8) and a CiteScore (9.9). They come from different systems and use different rules, so the two numbers are not interchangeable and the gap between them does not indicate an error. Compare a journal’s figure only with figures of the same type, from the same year, in the same subject category.

Using the figure responsibly

Clarivate’s own guidance on the impact factor (clarivate.com/academia-government/essays/impact-factor, read 8 November 2026) states: “The impact factor should not be used without careful attention to the many phenomena that influence citation rates.” Its cautions include:

Review articles tend to raise a journal’s figure.
Citation rates differ between fields, so compare only within a subject category.
A journal-level figure does not predict the citations of any single paper.
It should be used alongside informed peer review, not in place of it.

For responsible-assessment context, see how other journals’ figures are described in the CASRAI terms for Frontiers’ impact factor, Frontiers in Immunology and PLOS ONE.

Sources

Frontiers in Microbiology journal page and About page, frontiersin.org/journals/microbiology, read 8 November 2026.
Clarivate, The Clarivate Impact Factor, clarivate.com/academia-government/essays/impact-factor, read 8 November 2026.

Use in your systems

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