Comprehensive Calculator Guide
This calculator works out a journal’s impact factor: the average number of citations received in a year by the papers it published in the previous two years. 600 citations this year to the 250 papers published over the last two years gives an impact factor of 2.4. It helps researchers compare journals and understand the figure universities quote.
How it’s calculated
The 2025 impact factor = citations in 2025 to items published in 2023 and 2024 ÷ the citable items (mainly research articles and reviews) published in those two years. Clarivate publishes the official figures in the Journal Citation Reports, for journals indexed in Web of Science.
It is an average that a few highly cited papers can lift, and it varies widely by field, so only compare journals within a field. The DORA declaration warns against using it to judge individual researchers.
How to Use
- Enter this year’s citations to papers from the previous two years.
- Enter the number of papers published in each of those years.
- Press “Calculate” to see the impact factor and what it means.
Formula Used
Impact factor = citations ÷ (items last year + items the year before)
Practical Examples
- Example 1
- 120 then 130 papers and 600 citations: 600 ÷ 250 = 2.4.
- Example 2: a small journal
- 28 then 32 papers and 90 citations: 90 ÷ 60 = 1.5.
Important Tips
- Compare within the field, or by quartile (Q1–Q4).
- Check the journal is really indexed in Web of Science or Scopus.
- Weigh review speed, audience and fit alongside the number.
Common Mistakes to Avoid
- Comparing a medical journal with a mathematics journal.
- Trusting an impact factor a journal advertises without checking JCR.
- Counting citations to all of a journal’s papers, not just the last two years’.
Frequently Asked Questions
- What is a good impact factor?
- It depends on the field; look at the journal’s quartile among journals in its subject.
- Where do I find the official figure?
- In Clarivate’s Journal Citation Reports, often available through university libraries.
- Is it the same as CiteScore?
- No. CiteScore is Scopus’s metric, counting citations over four years and more document types.