You can download LAMMPS as a tarball from this page, using the "Download Now" button below.
There are several ways to get the LAMMPS software, either as a tarball, or from an active repository, or in executable form:
With source code, you have to build LAMMPS using "cmake" or "make". But you have more flexibility as to what features to include or exclude in the build. If you plan to modify or extend LAMMPS, then you need the source code.
The Install doc page lists what is included in the LAMMPS distribution.
Select the code you want, click the "Download Now" button, and your browser should download a gzipped tar file. Unpack it with the following command, and see the README file to get started.
tar -xzvf file.tar.gz
There have been ~316,000 downloads of LAMMPS from Sept 2004 thru Dec 2018.
All versions of LAMMPS are distributed under the terms of the GNU Public license. The earlier Fortran versions are no longer under active development.
To determine what version of LAMMPS you already have, see this page. If you download a tarball and want to stay current as features or bug-fixes are added to LAMMPS, see the Install patch doc page.
You can download older versions of LAMMPS, by going to this page and selecting the version you want, based on the date in the tarball file name. Not every version is available, because LAMMPS is updated frequently, and we have limited space on the Sandia web server.
Older parallel MD codes (ParaDyn, LJ) and the Python-based Pizza.py package, which provides pre- and post-processing and viz tools for LAMMPS, are available for download from this page.