Steam97 Excel Add-In

Steam Tables for Excel based on IAPWS-IF97 (32 bit & 64 bit)

For Excel 2010 (32 bit & 64 bit) / 2013 (32 bit & 64 bit) / 2016 (32 bit & 64 bit) / 2019 (32 bit & 64 bit) / 2021 or 365 desktop (32 bit & 64 bit)

Operating system Windows 7 / Windows 8 / Windows 8.1 / Windows 10 / Windows 11.

Steam97 Excel Add-In

Mollier Diagrams   BONUS

Each license for the Steam97 Excel Add-In also includes a free license for the Steam97 Desktop Application ($200 value).

The Steam97 Desktop Application allows calculation of steam properties and the display of calculated properties on Mollier (Steam) Diagrams, printing of diagrams etc...

This offer cannot be combined with any other offer that we might have.

About Steam 97 Excel Add-In

The Steam97 Excel Add-In library calculates 30 thermodynamic and transport properties of water and steam in SI and English units.

It allows 16 different combinations of input variables to be used for calculations.

Input variables that can be used are:

  •  1 Pressure
  •  2 Temperature
  •  3 Enthalpy
  •  4 Entropy
  •  5 Volume
  •  6 Internal energy
  •  7 Steam quality

The library is fully integrated in Excel, and available functions can be used in the same way as any other Excel function.

Main features of the library:
  • Professional quality, industrial strength software, proven in real world applications for more than 20 years
  • Based on the international standard formulation (IAPWS-IF97)
  • License includes 32 bit and 64 bit version of the library
  • Developed in C++ for maximum speed, thoroughly tested for accuracy
  • Extend the library with User Defined Functions (UDF)
  • Call Steam97 functions from VBA (samples are included in the release version)
  • Easy to install and easy to use
  • One year free technical support

The following figure shows a sample spreadsheet included in the download package.

Steam97 Excel Add-In

Steam97 Excel Add-In - Sample calculations in Excel

Used Formulations

The library uses new industrial formulation for steam tables, called "IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam (IAPWS-IF97)", and replaces the previous industrial formulation for steam tables, IFC-67.

IAPWS-IF97 improves significantly both accuracy and speed of the calculation of the thermodynamic properties compared with the old formulation.

For transport properties calculations are based on the latest internationally accepted equations also available from IAPWS.

The Steam97 Excel Add-In libraries cannot be shipped to a third party as a part of your VBA application. If you need a royalty free library please refer to the Steam97 ActiveX DLL.

System Requirements

Operating system Windows 7 / Windows 8 / Windows 8.1 / Windows 10 / Windows 11.

Excel 2010 (32 bit & 64 bit) / 2013 (32 bit & 64 bit) / 2016 (32 bit & 64 bit) / 2019 (32 bit & 64 bit) / 2021 or 365 desktop (32 bit & 64 bit).

User privileges
Installation and use of the library requires standard user privileges or better.

Steam Functions

Compact Design   IMPORTANT

This software is designed to be easy to use. There are 32 functions (16 for SI units and 16 for English/Imperial units). Each function can calculate 30 properties. As a concesquence the library covers 16*2*30 = 960 combinations.

Instead of creating hundreds of functions, the library provides access to steam properties covering 960 combinations in only 32 functions. This significatly reduces the learning curve and simplifies the use of the library.

The following functions are available in the Steam97 Excel Add-In:

Function List in SI and E units - Steam97 Excel Add-In v3.1
  # Function Name
 SI Units
 Function Name
 English Units
 Argument 1
 Argument 2
 Argument 3
 Valid in
  1 SatPXsi SatPXe p x propertyID saturation
  2 SatTXsi SatTXe t x propertyID saturation
  3 SteamPTsi SteamPTe p t propertyID all
  4 SteamPHsi SteamPHe p h propertyID all
  5 SteamPSsi SteamPSe p s propertyID all
  6 SteamPUsi SteamPUe p u propertyID all
  7 SteamPVsi SteamPVe p v propertyID all
  8 SteamTHsi SteamTHe t h propertyID all
  9 SteamTSsi SteamTSe t s propertyID all
 10 SteamTUsi SteamTUe t u propertyID all
 11 SteamTVsi SteamTVe t v propertyID all
 12 SteamHSsi SteamHSe h s propertyID all
 13 SteamHVsi SteamHVe h v propertyID all
 14 SteamUSsi SteamUSe u s propertyID all
 15 SteamUVsi SteamUVe u v propertyID all
 16 SteamVSsi SteamVSe v s propertyID all

  • "all" means valid in all 5 regions as defined by the IAPWS-IF97, see the diagram at the bottom of the page.
  • The third argument "propertyID" specifies which property to calculate, see the "Steam Properties" table below.
  • Since "propertyID" is string type it must be enclosed in quotes, see an example below.

To download a list of all available functions in the PDF format, switch to the "Downloads" tab and go to a section "Quick reference documents".

Functions Notation

In order to easily identify functions to be used, function names are formated using the following rules:

  • Functions applicable only in the saturation region, as defined by the IAPWS-IF97, start with Sat
  • Functions applicable in all regions, as defined by the IAPWS-IF97, start with Steam
  • Next follow two capital letters denoting the first and the second input parameters of a function, for example PT stands for pressure and temperature respectively
  • Function names ending with si mark functions to be used for calculations in SI Units
  • Function names ending with e mark functions to be used for calculations in English Units


To calculate specific heat in SI Units in any of the regions as defined by the IAPWS-IF97 based on available enthalpy and entropy as input, use the following:
  •  1 h = 51.2 kJ/kg
  •  2 s = 0.15 kJ/(kg·K)
  •  3 the third argument is a string which specifies the property to be calculated by suppling the appropriate propertyID

See values of propertyIDs in the Steam Properties table below.

Based on the above provided description, the following should be entered into a cell or the formula bar:
=SteamHSsi(h, s, "cp")

Steam Properties

The following thermodynamic and transport properties can be calculated with Steam97 Excel Add-In:

Calculable properties in SI or E units - Steam97 Excel Add-In v3.1
  # Property Name Property ID SI Units English Units
  1 Pressure p bar psi
  2 Temperature t °C °F
  3 Density d kg ⁄ m³ lb ⁄ ft³
  4 Specific volume v m³ ⁄ kg ft³ ⁄ lb
  5 Specific enthalpy h kJ ⁄ kg Btu ⁄ lb
  6 Specific entropy s kJ ⁄ (kg•K) Btu ⁄ (lb•°F)
  7 Specific internal energy u kJ ⁄ kg Btu ⁄ lb
  8 Specific isobaric heat capacity cp kJ ⁄ (kg•K) Btu ⁄ (lb•°F)
  9 Specific isochoric heat capacity cv kJ ⁄ (kg•K) Btu ⁄ (lb•°F)
 10 Speed of sound w m ⁄ s ft ⁄ s
 11 Isentropic exponent kapa - -
 12 Specific Helmholtz free energy H kJ ⁄ kg Btu ⁄ lb
 13 Specific Gibbs free energy G kJ ⁄ kg Btu ⁄ lb
 14 Compressibility factor Z - -
 15 Steam quality x % %
 16 Region region - -
 17 Isobaric volume expansion coefficient alpha 1 ⁄ K 1 ⁄°F
 18 Isothermal compressibility Kt 1 ⁄ MPa 1 ⁄ psi
 19 Partial derivative (dV/dT)p dvdt m³ ⁄ (kg•K) ft³⁄(lb•°F)
 20 Partial derivative (dV/dP)T dvdp m³ ⁄ (kg•MPa) ft³ ⁄ (lb•psi)
 21 Partial derivative (dP/dT)v dpdt MPa ⁄ K psi ⁄ °F
 22 Partial derivative (dP/dV)T dpdv MPa•kg ⁄ m³ psi•lb ⁄ ft³
 23 Isothermal Joule-Thomson coefficient iJTC kJ ⁄ (kg•MPa) Btu ⁄ (lb•psi)
 24 Joule-Thomson coefficient JTC K ⁄ MPa °F ⁄ psi
 25 Dynamic viscosity dv µPa•s lb ⁄ (ft•h)
 26 Kinematic viscosity kv mm² ⁄ s ft²/h
 27 Thermal conductivity tc W ⁄ (K•m) Btu ⁄ (h•ft•°F)
 28 Thermal diffusivity td mm² ⁄ s ft² ⁄ h
 29 Prandtl number Pr - -
 30 Surface tension Sigma mN ⁄ m lbf ⁄ ft

To download a list of all available properties in the PDF format, switch to the "Downloads" tab and go to the section "Quick reference documents".

Range of Validity

The entire set of equations of the IAPWS-IF97, used by the library for calculation of thermodynamic properties, is defined by the following temperature and pressure range:

  • 273.15 K <= T < = 1073.15 K    p < = 100 MPa
  • 1073.15 K < T < = 2273.15 K    p < = 50 MPa

Steam97 Range of Validity

Fig.1 Steam table regions defined in the IAPWS-IF97


The following screenshots demonstrate how to use the library, it's a 4 step process.

1.(a) Start Excel and press the "Insert Function" toolbar button.

Insert Function toolbar button

1.(b) Alternatively, start Excel and press the "Insert Function" menu item.

Insert Function menu item

2. Select a Steam97 library (SI or English units).

Select Steam97 library

3. Select a function and press the OK button.

Select Function - Steam97 library

4. Enter input parameters and press the OK button.

Calculate Steam97 properties

NOTE: You don't have to put quotes around the property ID, they are inserted automatically.

That's it, the result will be displayed in the selected cell.

Steam97 VBA Programming

The release version of the Steam97 Excel Add-In library contains "modCallFunction" module which provides VBA wrapper utility functions.

The utility function CallFunction makes it easy to call Steam97.xll functions from VBA. For more information please refer to the help file provided in both demo and release versions.

Example 1

This excerpt from the code demonstrates how to calculate heat of evaporation for given saturation temperature.

  1. 'Calculate saturation pressure for given temperature
  2. ps = CallFunction("SatTXsi", t, xLiquid, "p")
  3. Worksheets("Heat of Evaporation").Cells(row, 2).Value = ps
  4. 'Calculate specific enthalpy of the liquid on the saturation line
  5. hLiquid = CallFunction("SatTXsi", t, xLiquid, "h")
  6. Worksheets("Heat of Evaporation").Cells(row, 3).Value = hLiquid
  7. 'Calculate specific enthalpy of the vapor on the saturation line
  8. hVapor = CallFunction("SatTXsi", t, xVapor, "h")
  9. Worksheets("Heat of Evaporation").Cells(row, 4).Value = hVapor
  10. 'Calculate heat of evaporation
  11. delta_h = hVapor - hLiquid
  12. Worksheets("Heat of Evaporation").Cells(row, 5).Value = delta_h

Example 2

This excerpt from the code demonstrates how to calculate steam turbine efficiency.

  1. 'Calculate specific enthalpy
  2. hIn = CallFunction("SteamPTsi", pIn, tIn, "h")
  3. Worksheets("Steam Turbine").Cells(row, 3).Value = hIn
  4. 'Calculate specific entropy
  5. sIn = CallFunction("SteamPTsi", pIn, tIn, "s")
  6. Worksheets("Steam Turbine").Cells(row, 4).Value = sIn
  7. Worksheets("Steam Turbine").Cells(row, 5).Value = pOut
  8. Worksheets("Steam Turbine").Cells(row, 6).Value = tOut
  9. 'Calculate specific enthalpy
  10. hOut = CallFunction("SteamPTsi", pOut, tOut, "h")
  11. Worksheets("Steam Turbine").Cells(row, 7).Value = hOut
  12. 'Calculate specific enthalpy
  13. hs = CallFunction("SteamPSsi", pOut, sIn, "h")
  14. Worksheets("Steam Turbine").Cells(row, 8).Value = hs
  15. 'Calculate steam turbine efficiency
  16. eta = (hIn - hOut) / (hIn - hs) * 100
  17. Worksheets("Steam Turbine").Cells(row, 9).Value = eta


The setup program will automatically install the library in Excel.

To install the library successfully you must have at least standard user privileges on your computer.


The built-in ZIP support on Windows 10 is buggy and sometimes cannot open a valid (not empty) zip file.

Use 7-zip (free and open source) or some other reliable program for zip file processing.

Steam97 Excel Add-In library

For Excel 2007 / 2010 (32 bit) / 2013 (32 bit) / 2016 (32 bit) / 2019 (32 bit) / 365 desktop (32 bit)

- Download Steam97 Excel Add-In version (3.1) - demo (32 bit)

Steam97 Excel Add-In library

For Excel 2010 (64 bit) / 2013 (64 bit) / 2016 (64 bit) / 2019 (64 bit) / 365 desktop (64 bit)

- Download Steam97 Excel Add-In version (3.1) - demo (64 bit)

You can also evaluate the Steam Tables library (based on IAPWS-IF97) online, visit Steam Tables Calculator web application. It uses the same calculation engine as the Steam97 Excel Add-In.

Quick reference documents

- List of available properties in Steam97 Excel Add-In

- List of available functions in Steam97 Excel Add-In

Steam diagrams

- logP-H diagram in SI units generated with Steam97 Excel Add-In

Price info

Prices subject to change without notice!

  • A license includes 32 bit and 64 bit versions of the Steam97 Excel Add-In library
  • A license also includes the Steam97 Desktop Application (calculate properties, mollier diagrams, printing...)

Steam97 Excel Add-In version 3.1
1-4 licensesUSD 279.95 per copy
5-20 licensesUSD 249.95 per copy
21 > licensesUSD 224.95 per copy
Company wide licenseUSD 11995.00


Each license also includes the following:

  • One year free e-mail technical support
  • One year free minor version updates if available (for example 3.2, 3.x up to, but not including version 4.0)

If you have any questions, please don't hesitate to contact sales. Contact information is provided on the following page:

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General Information

For quick access to the Steam97 Excel Add-In, you may purchase and download our product using automated and secure online ordering system.
After ordering, you will receive a notification mail with further instructions for how to download and install the software.

The Registration includes a free subscription program. Each Registered user will be receiving bug fixes and technical support for the registered version within one year.

Shipping by the postal mail is not available.

How to order

1. Internet ordering

Available ordering options (open an order form to select):

  • Credit Card (Visa®, Mastercard®, American Express®, Discover®)
  • PayPal
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To buy a specific number of licenses for the Steam97 Excel Add-In click the button: Open order page for the Steam97 Excel Add-In.

To purchase a Company Wide License contact sales. Contact information is provided on the following page:
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2. Bank Direct Payment

If you prefer to pay for the product by "Bank Direct Payment", contact sales. Contact information is provided on the following page:

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