TEOS-10 software packages

Gibbs-SeaWater (GSW) Oceanographic Toolbox

The Gibbs-SeaWater (GSW) Oceanographic Toolbox contains the TEOS-10 subroutines for evaluating the thermodynamic properties of pure water (using IAPWS-09) and seawater (using IAPWS-08 for the saline part). The GSW library does not provide properties of ice or moist air (these properties can be found in the SIA library). This GSW Oceanographic Toolbox does not adhere to strict basic-SI units but rather oceanographic units are adopted.

Note that all the information buttons on the left below are independent of MATLAB, FORTRAN, C or PHP while the buttons on the right are for downloading the GSW Oceanographic Toolbox in these computer languages. The GSW Toolbox contents is particularly useful because it provides links to web pages which describe the thermodynamic theory behind each of the functions. Many of these web pages are intended to assist oceanographers gain confidence with the TEOS-10 thermodynamic approach to seawater. Again, you can access this information from these links on the left below without having MATLAB or being a MATLAB user.

If you use the GSW Oceanographic Toolbox we ask that you include a reference to McDougall and Barker (2011), whose full citation is:
McDougall, T.J. and P.M. Barker, 2011: Getting started with TEOS-10 and the Gibbs Seawater (GSW) Oceanographic Toolbox, 28pp., SCOR/IAPSO WG127, ISBN 978-0-646-55621-5.

To install the GSW Toolbox in MATLAB
you MUST add all the SUBFOLDERS to the PATH,
then you MUST run "gsw_check_functions".
See Installation instructions below for the complete installation instructions.

Installing the GSW Toolbox Contents of the GSW Toolbox
Getting started with TEOS-10 GSW Toolbox list
GSW Toolbox version history Abridged GSW Toolbox list
GSW licence Corresponding Seawater functions in the GSW Toolbox
GSW Oceanographic Toolbox GSW Oceanographic Toolbox
GSW Oceanographic Toolbox GSW Oceanographic Toolbox
GSW Oceanographic Toolbox GSW Oceanographic Toolbox

The Python version is developed at, from which the latest source code can be downloaded. For most users, however, using a conda-based Python distribution (miniconda, or Anaconda) is highly recommended. The conda-forge channel provides the latest release, installable with a simple command:

"conda install -c conda-forge gsw"

R users can access TEOS-10 algorithms through the gsw package. This package is hosted on the Comprehensive R Archive Network, and so it is installed from within R itself, by typing


in an R session. The current gsw version (1.0-5) is based on GSW-C version 3.0-5 (git commit 5b4d959e54031f9e972f3e863f63e67fa4f5bfec at The CRAN gsw web page provides check results, an issue tracker, a reference manual, a vignette, and a link to a supplemental webpage at

If you have any questions reguarding the software listed on this page email

The GSW toolbox has been developed in Maltab. It is currently being translated into other languages, if you wish to see the current progress or wish to participate in translating the code visit the development repository at

Seawater-Ice-Air (SIA)

The Seawater-Ice-Air (SIA) library contains the TEOS-10 subroutines for evaluating a wide range of thermodynamic properties of pure water (using IAPWS-95), seawater (using IAPWS-08 for the saline part), ice Ih (using IAPWS-06) and for moist air (using Feistel et al. (2010a), IAPWS (2010)). As a general rule, the inputs and the outputs of the algorithms in the SIA library are in basic SI units. Hence the salinity is Absolute Salinity in units of kg/kg (so that for example standard ocean Reference Salinity is input to SIA functions as 0.035 165 04 kg/kg rather than 35.16504 g/kg, in situ temperature is input as Absolute Temperature (T) in K, and pressure is input as Absolute Pressure (P) in Pa.