SMath Studio - Tiny, powerful, free mathematical program with WYSIWYG editor and complete units of measurements support.

CHEMCAD - We equip chemical engineers with integrated and intuitive process simulation software to tackle projects large and small. Discover how CHEMCAD can help you design, analyze and measure simple and complex processes like never before.

PTC Mathcad - PTC Mathcad PTC Mathcad is Engineering Math Software That Allows You to Perform, Analyze, and Share Your Most Vital Calculations.

Aspen HYSYS - Aspen HYSYS is a software solution for chemical process simulation and modeling.

EngineeringPaper.xyz - Online app for engineering calculations. Solves systems of equations, checks and converts units automatically, supports plotting, and allows for the creation of a link to share your work. Free and open source, no registration required.

gPROMS - Oil and Gas Simulation and Modeling