nauty and Traces are programs for computing automorphism groups of graphs and digraphs [*]. They can also produce a canonical label. They are written in a portable subset of C, and run on a considerable number of different systems.

There is a small suite of programs called gtools included in the package. For example, geng can generate non-isomorphic graphs very quickly. There are also generators for bipartite graphs, digraphs, and multigraphs, and programs for manipulating files of graphs in a compact format.

[*] At present, Traces does not accept digraphs.


A complete manual is included in the package. It is also separately available here.

The original design of nauty is in McKay, B.D., Practical Graph Isomorphism, Congressus Numerantium, 30 (1981) 45-87. A scan (2.6 MB) is available.

The original design of Traces is in in Piperno, A., Search Space Contraction in Canonical Labeling of Graphs, available at

The current algorithms behind nauty and Traces are described in the paper McKay, B.D. and Piperno, A., Practical Graph Isomorphism, II, Journal of Symbolic Computation, 60 (2014), pp.94-112. The paper is available online here. A preliminary version is available at


How to cite nauty or Traces

If you use nauty or Traces in your research, please cite this paper (a BibTex entry is here): McKay, B.D. and Piperno, A., Practical Graph Isomorphism, II, J. Symbolic Computation, 60 (2014), pp. 94-112,

How to get it

If you agree to the restrictions listed below, you may fetch version 2.5 (r9) of nauty, and version 2.0 of Traces, as a gzipped tar file (∼1 MB).

See the file changes24-25.txt for a summary of recent changes.

The package uses the GNU autoconf installation system. You are advised to read the file README before compiling anything.

Installation procedure

   tar xvzf nauty25r9.tar.gz
   cd nauty25r9

After this procedure, the directory nauty25r9 contains all the executables. Move them somewhere else as you wish.

Dreadnaut users

Type An to enter nauty dense mode, As for nauty sparse mode, At for Traces mode. Type an additional + to convert the current graph. With a few exceptions, all dreadnaut commands are available in every mode. See the manual for a full description of the new features.


nauty and traces is subject to the following usage restrictions:

nauty is copyright (1984-2014) Brendan McKay. All rights reserved. Traces is copyright (2008-2014) Adolfo Piperno. All rights reserved. Permission is hereby given for use and/or distribution with the exception of sale for profit or application with nontrivial military significance. You must not remove this copyright notice, and you must document any changes that you make to this program. This software is subject to this copyright only, irrespective of any copyright attached to any package of which this is a part.
Absolutely no guarantees or warranties are made concerning the suitability, correctness, or any other aspect of this program. Any use is at your own risk.

The above does not apply to the file planarity.c, which is copyright to the Magma project and distributed with nauty by permission, nor to the file watercluster2.c, which is copyright to Gunnar Brinkmann.