ATSAS Software

ATSAS is the world most comprehensive and powerful program suite for Small Angle Scattering data analysis from biological macromolecules in solution. The suite is freely available for academic users upon registration. BIOSAXS offers various types of licenses for commercial customers.
See What's new in ATSAS 3.2.1 here.
With ATSAS you can:

  • evaluate the overall geometrical parameters of your sample (radius of gyration (Rg), molecular weight etc.);
  • reconstruct the shape of proteins and other macromolecules in solution ab initio (i.e. based only on SAXS data);
  • build models using data from complementary methods (X-ray crystallography, NMR, bioinformatics etc.);
  • analyse oligomeric mixtures and flexible systems (including intrinsically disordered proteins).

ATSAS includes a number of programs with a graphical user interface (GUI) for interactive data analysis. On the screenshot above, clockwise: PRIMUS for processing of experimental data; interactive Guinier analysis provides Rg and I(0) estimates; GNOM is an indirect Fourier transform program that provides the pair distance distribution function p(r); below the Guinier window is the program Chromixs.

ATSAS includes a number of command-line tools which are useful for automation of processing of large amounts of experimental data.

ATSAS is installed as a single package where all programs, libraries and manuals are included. 64 bit installation packages are available for:

  • Windows 10 and 11;
  • macOS 11 (Big Sur), 12 (Monterey) and 13 (Ventura) (all: x86_64 only);
  • Ubuntu 20.04 and 22.04;
  • Oracle Linux 8.

If your operating system is not in this list, customized installations may be possible, please contact us at

Commercial ATSAS licenses

We offer single- and multi-user ATSAS licenses. For 2024, the license period has been increased by one additional year. Get your 2 years license for the price of one year! Please contact us at for a price offer.