What is the h-index, and how do you calculate it?

How to calculate the h-index

1. List every paper with its citation count.
2. Sort the list from most to least cited.
3. Go down the list, numbering the papers 1, 2, 3 …
4. The h-index is the last position where the paper's citation count is still greater than or equal to its position.

Example: six papers cited 25, 12, 8, 5, 4 and 1 times. Position 4 has 5 citations (5 ≥ 4); position 5 has 4 citations (4 ≥ 5 is false). The h-index is 4. Adding a seventh paper with 2 citations changes nothing — the h-index rewards papers that keep being cited.

To compute one from a list of DOIs or titles, paste them into the research impact tracker, which looks up each work's citations in OpenAlex.

Where to find your h-index — and why the numbers differ

• Google Scholar — broadest coverage, including theses, preprints and some grey literature, so its h-index is usually the highest. It also shows the i10-index, the number of papers with at least ten citations.
• Scopus — a curated index of journals, conference proceedings and books; author profiles are generated automatically and can be corrected on request.
• Web of Science — the most selective coverage, so the h-index is often the lowest.
• OpenAlex — a free, open index of more than 250 million works that anyone can query.

Always state the source and the date when you report an h-index, and compare people only within the same database.

What is a good h-index?

There is no universal threshold. Citation habits differ hugely between fields — biomedicine cites far more than mathematics — and the h-index grows with career length, because papers need years to collect citations. In his 2005 paper Hirsch suggested that, for physicists at major research universities, an h-index of about 12 might be typical for promotion to tenure and about 18 for full professor; those figures were for one field, two decades ago.

Two adjustments make comparisons fairer: the m-quotient, also from Hirsch, divides the h-index by the years since your first paper; and comparing within a field and career stage, not across them.

Variants you will meet

• i10-index (Google Scholar) — papers with at least ten citations.
• h5-index (Google Scholar Metrics) — the h-index of a journal's articles from the last five complete years; used to rank venues.
• g-index — gives more weight to highly cited papers.
• m-quotient — h divided by career length in years.

What the h-index cannot tell you

• It ignores author order and contribution: a paper with 200 authors counts in full for each of them.
• It never falls as citations accumulate, so it favours long careers.
• Self-citation and citation circles can inflate it.
• It says nothing about the quality of an individual paper.

That is why the San Francisco Declaration on Research Assessment (DORA) and the Leiden Manifesto for research metrics both recommend judging research on its content, with metrics only as support.

Raising your h-index the legitimate way

• Publish in venues your field reads; the journal finder ranks journals that published work like yours.
• Make papers findable: an ORCID iD, a consistent name, and open-access copies or preprints where the publisher allows.
• Write titles and abstracts that say what you found — see how to write an abstract.
• Cite your earlier work only where it is genuinely relevant.