Erdős Number Calculator
Type a mathematician’s or scientist’s name and this Erdős number calculator shows whether they are Paul Erdős himself, one of his 514 coauthors, or one of the 13,782 people with Erdős number 2, together with the coauthors who link them to Erdős.
Any order, accents optional. Part of a name is enough, such as a surname.
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Collaboration Distance to Paul Erdős
An Erdős number counts the steps of joint authorship between a researcher and Paul Erdős, the prolific Hungarian mathematician. His coauthors have number 1, their coauthors number 2, and so on. The Erdős number calculator answers that question for the two innermost circles.
Built on the Erdős Number Project
Results come from the lists kept by Jerry Grossman’s Erdős Number Project at Oakland University, which records every coauthor of Erdős and everyone who has written with one of them, based on Mathematical Reviews.
The Path, Not Just the Number
For every match the Erdős number calculator shows the chain of coauthors that leads to Erdős, the year of the first joint paper and the number of joint papers, so you can see why the number is what it is.
Why Use Our Erdős Number Calculator?
Instant Search Across 14,000+ Names
Partial names, any word order and missing accents still match, so a quick surname search is enough. The Erdős number calculator lists up to 25 matches at once and ranks exact surname hits first.
Free and Without an Account
There is no subscription and no sign-up, unlike many library databases. Look up yourself, your advisor or famous scientists such as Einstein and Knuth as often as you like.
Browse all free toolsWorks Out Your Own Number
If you are not listed, search for your coauthors instead: your Erdős number is at most one more than the lowest of theirs, and each result card states that bound.
Cite a coauthor’s paper with DOI to BibTeXHow to Use It in 3 Steps
Step 1: Type a Name
Enter a full name or just a surname in the Erdős number calculator, in any order and with or without accents.
Step 2: Read the Number and Path
Each match shows its Erdős number in the badge, then the coauthor path to Paul Erdős with the people who link them.
Step 3: Go Further If Needed
If nobody matches, look up your coauthors and add one, or use the AMS collaboration distance tool, which covers numbers of 3 and beyond.
Convert your paper to LaTeXOfficial references: AMS collaboration distance (MathSciNet)
Erdős Number Calculator FAQ
- What is an Erdős number?
- It is the number of coauthorship links between a person and Paul Erdős. Erdős has number 0, people who wrote a paper with him have 1, their coauthors have 2, and someone with no chain to him has an infinite Erdős number.
- What is an Erdős–Bacon number?
- It is the sum of a person’s Erdős number and their Bacon number, the steps from Kevin Bacon through shared film roles. Only a few people have both, mostly scientists who appeared in films or actors who published research.
- What is an Erdős–Bacon–Sabbath number?
- It adds a third link, the Sabbath number, counting steps through musical collaborations to the band Black Sabbath. The total is a light-hearted measure of how connected someone is across science, film and music.
- How to calculate an Erdős number?
- Find the shortest chain of joint papers from the person to Erdős and count the links. With this Erdős number calculator you search the name; if it is not listed, check coauthors, since your number is one more than the smallest of theirs.
- What is my Erdős number?
- Search your name above. If you appear, the badge shows 1 or 2. If not, search each coauthor: your Erdős number is at most one more than the lowest number you find, or use the AMS tool for the exact distance.
- What is a good Erdős number?
- Most active mathematicians have an Erdős number between 2 and 5, and the median is around 5. A number of 1 or 2 is rare, and anything up to 4 is common among researchers in mathematics and computer science.
- What is Kevin Bacon’s Erdős number?
- Kevin Bacon is not known to have coauthored a research paper, so he has no finite Erdős number. He is famous instead as the centre of the Bacon number, the film-world counterpart of the Erdős number.
- How many people have Erdős number 1, 2 or 3?
- The Erdős Number Project lists 514 people with Erdős number 1 and 13,782 with Erdős number 2. Those with number 3 run to tens of thousands, too many for the project to list.
- Can your Erdős number go up?
- No. Papers are never unwritten, so a path can only get shorter as you or your coauthors publish with people closer to Erdős. Your Erdős number can stay the same or go down, never up.
- Why is the Erdős number important?
- It is mostly a friendly bit of academic folklore, but it also illustrates how small the scientific collaboration network is, and researchers use it to study how mathematicians work together.
- Where should I put my Erdős number?
- People mention it on a personal homepage, an academic profile or the fun-facts part of a CV. It is not a measure of research quality, so keep it out of formal grant or job applications.
- How do I use the AMS MathSciNet collaboration distance tool?
- Open the free AMS collaboration distance page, enter Paul Erdős and the other author as they appear in Mathematical Reviews, and it returns the shortest coauthor chain between them, including numbers above 2.
- Does the Erdős number calculator work for computer scientists?
- Yes, if their joint papers are indexed in Mathematical Reviews, which covers much of theoretical computer science. Many computer scientists, Donald Knuth among them, have Erdős number 2.
- Can I find my Erdős number with Google Scholar?
- Not directly: Google Scholar has no collaboration-distance feature. You can use it to list your coauthors, then look each one up in this Erdős number calculator and add one to the lowest result.
- What is Paul Erdős’s own Erdős number?
- Zero. Paul Erdős (1913–1996) is the starting point of the measure. Search “Erdős” above and he appears first with the number 0.
- Is there a free Erdős number calculator online?
- Yes, this one is free and needs no sign-up. It covers Erdős numbers 0, 1 and 2 from the Erdős Number Project, and the free AMS collaboration distance tool covers longer paths.
- Where does the Erdős number data come from?
- From the Erdos1 and Erdos2 lists of the Erdős Number Project at Oakland University, in the versions of August 2025. They are based on Mathematical Reviews and are updated every few years.
- Why can’t the calculator find my name?
- The Erdős number calculator only lists Erdős numbers 0, 1 and 2. Your number may be 3 or more, your papers may not be indexed in Mathematical Reviews, or your name may be recorded with a different spelling or initials.
- How should I type a name to search?
- Type the surname alone or the full name in any order. Accents are optional, so Erdos finds Erdős, and part of a word is enough, so Pomer finds Pomerance.
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