pyGAPS (Python General Adsorption Processing Suite) is a framework for adsorption data analysis and fitting, written in Python 3.


Project Status: Active – The project has reached a stable, usable state and is being actively developed. Commits since latest release


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PyPI Package latest release PyPI Wheel
Supported versions Supported implementations


  • Advanced adsorption data import and manipulation.

  • Routine analysis such as BET/Langmuir surface area, t-plots, alpha-s plots, Dubinin plots etc.

  • Pore size distribution calculations for mesopores (BJH, Dollimore-Heal).

  • Pore size distribution calculations for micropores (Horvath-Kawazoe).

  • Pore size distribution calculations using kernels (DFT, QSDFT, ...)

  • Isotherm fitting with various models (Henry, Langmuir, DS/TS Langmuir, etc..)

  • Isosteric enthalpy of adsorption calculations.

  • IAST predictions for binary and multicomponent adsorption.

  • Parsing to and from multiple formats such as AIF, Excel, CSV and JSON.

  • Simple methods for isotherm graphing and comparison.

  • An database backend for storing and retrieving data.


pyGAPS is built with three key mantras in mind:

  • Opinionated: there are many places where the code will suggest or default to what the it considers a good practice. As examples: the standard units, pore size distribution methods and BET calculation limits.

  • Flexible: while the defaults are there for a reason, you can override pretty much any parameter. Want to pass a custom adsorbate thickness function or use volumetric bases? Can do!

  • Transparent: all code is well documented and open source. There are no black boxes.

In-depth explanations, examples and theory can be found in the online documentation. If you are familiar with Python and adsorption and want to jump right in, look at the quickstart section. Examples for each of the capabilities specified above can be found documented here. Most of the pages are actually Jupyter Notebooks, you can download them and run them yourself from the /docs/examples folder.

To become well familiarised with the concepts introduced by pyGAPS, such as what is an Isotherm, how units work, what data is required and can be stored etc., a deep dive is available in the manual.

Finally, having a strong grasp of the science of adsorption is recommended, to understand the strengths and shortcomings of various methods. We have done our best to explain the theory and application range of each capability and model. To learn more, look at the reference or simply call help() from a python interpreter (for example help(pygaps.PointIsotherm).

Support and sponsorship#

This project is graciously sponsored by Surface Measurement Systems, by employing Paul Iacomi, the core maintainer. The work would not be possible without their contribution, keeping this open source project alive.

If you are interested in implementing a particular feature, or obtaining professional level support, contact us here Bugs or questions?.


Please consider citing the related paper we published if you use the program in your research.

Paul Iacomi, Philip L. Llewellyn, Adsorption (2019). pyGAPS: A Python-Based Framework for Adsorption Isotherm Processing and Material Characterisation. DOI:


The easiest way to install pyGAPS is from the command line. Using pip for example:

pip install pygaps

or Anaconda/Conda:

conda install -c conda-forge pygaps

If you are just starting out, Anaconda/Conda is a good bet since it manages virtual environments for you. Check out Installation for more details.


To install the development branch, clone the repository from GitHub. Then install the package with pip either in regular or developer mode.

git clone

# then install
pip install ./pyGAPS

# or in editable/develop mode
pip install -e ./pyGAPS

If you want to contribute to pyGAPS or develop your own code from the package, check out the detailed information in CONTRIBUTING.rst.

Bugs or questions?#

For any bugs found, please open an issue or, even better, submit a pull request. It'll make my life easier. This also applies to any features which you think might benefit the project. I'm also more than happy to answer any questions. Shoot an email to mail( at ) or find me at or on Twitter.