h-index Explained: How to Calculate It, with Real Researcher Data

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Quick answerThe h-index is a single number that combines how many papers a researcher has published and how often they are cited. A researcher has an h-index of h if h of their papers have each been cited at least h times. For example, an h-index of 10 means 10 papers with at least 10 citations each.
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Paste your title, keywords or abstract. We match it against 28,582 journal papers published by PhD researchers on ScholarsColab and show where the closest work appeared, with each journal’s indexing (SCIE, SSCI, AHCI, ESCI, Scopus, JCR 2024).

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How it works: no AI or language model is used. Your words are matched against the titles of real published papers by our mentors; journals are ranked by how many closely matching papers they published. Indexing comes from the SCIE, SSCI, AHCI, ESCI, Scopus and JCR 2024 lists, matched by journal name; “not found in our indexing lists” does not prove a journal is unindexed. Always check a journal’s scope and current indexing before submitting.

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How to calculate an h-index

  1. List all papers with their citation counts.
  2. Sort them from most to least cited.
  3. Go down the list and find the last position where the citation count is still at least the position number.
  4. That position is the h-index.
Rank 1 2 3 4 5 6
Citations 48 21 9 5 4 1
At least as many as the rank? Yes Yes Yes Yes No No

In this example the h-index is 4: four papers have at least four citations each, but there are not five papers with at least five.

Real h-index data from PhD researchers

Across 891 ScholarsColab mentors with at least five dated papers, the median h-index calculated from their Google Scholar publication lists is 7; a quarter have an h-index of 13 or more.
h-index of ScholarsColab mentorsh-index 0–4289h-index 5–9281h-index 10–14139h-index 15–1964h-index 20–2958h-index 30–4947h-index 50+13
Number of mentors in each h-index range, calculated from their Google Scholar publication lists (mentors with at least five dated papers).

The h-index grows with career length, because papers need time to be cited. That is why comparing researchers at different career stages is unfair; see how the spread grows over a career in our guide to heteroskedasticity.

Why your h-index differs between databases

Source Usually Why
Google Scholar Highest Counts citations from more sources, including theses, preprints and books
Scopus Middle Counts citations from Scopus-indexed sources
Web of Science Often lowest Counts citations from its more selective collection

Strengths and limits

  • Strength: it rewards steady, cited work rather than one famous paper or many uncited ones.
  • Limit: it depends on field and career length.
  • Limit: it ignores author order and the number of co-authors.
  • Limit: self-citations can inflate it.

Frequently asked questions

What is a good h-index?

It depends on the field and career stage. Compare with researchers at a similar stage in the same field rather than using a single cut-off.

How is the h-index calculated?

Sort your papers by citations from highest to lowest; your h-index is the largest number h such that h papers have at least h citations each.

Why is my Google Scholar h-index higher than in Scopus?

Google Scholar counts citations from a wider range of sources, including some that Scopus and Web of Science do not index.

Does the h-index depend on the journals I publish in?

Indirectly. Papers in widely read, well-indexed journals tend to be cited more, which can raise your h-index over time.

What is the i10-index?

The i10-index, shown on Google Scholar, is the number of papers with at least 10 citations.

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About the data on this page. Journal suggestions and statistics come from the Google Scholar publication lists of PhD researchers who mentor on ScholarsColab, updated daily. Indexing is matched by journal name against the SCIE, SSCI, AHCI, ESCI, Scopus and JCR 2024 lists; a journal “not found in our indexing lists” may still be indexed under a different name, so always confirm on the official Web of Science Master Journal List or Scopus source list. Figures describe this group of researchers and may not apply to research as a whole.