USTChEX: A free numerical solver addin for MS Excel
USTChEX: A free numerical solver addin for MS Excel
Originally developed under Project XLSLANI and first released through Allan’s Stuff (now defunct), this Excel add-in was built to fill a long-standing gap in spreadsheet computation. Excel’s built-in toolset lacks many of the core numerical methods needed in engineering analysis—such as surface interpolation, numerical integration, ordinary differential equation (ODE) solvers, and multi-variable system solvers.
The USTCHEX version continues that work, providing an expandable library of numerical procedures and specialized chemical-engineering functions directly accessible from Excel formulas. While this section is still relatively barebones and under active development, future updates will broaden its scope to include more robust solvers, advanced thermodynamic routines, and shortcut calculations for complex process problems.
Download Links CURRENT VERSION: v1.2 (April 2026 release)
VERSION 1.2 (via MediaFire)
Added USTChEX Thermodynamics
Added Excel Ribbon containing formula buttons
Improved stability of BDF solvers
OLD VERSIONS:
VERSION 1.1 (via MediaFire)
USTChEX integrates directly into MS Excel, allowing numerical and thermodynamic calculations to be performed using simple worksheet formulas. Once installed, functions are accessible through both the Excel ribbon and standard formula input.
Supports interpolation, numerical integration, and ODE solvers
Includes thermodynamic property and VLE calculations
Built for direct use in engineering problem-solving and instruction
Quick Start
Download the latest version
Load the add-in in Excel
Use the ribbon or type =USTCHEX_... functions directly in cells. Documentation can be found here.
Last edited: December 28, 2025