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

myQuorum - myQuorum, a program for modeling and simulating chemical reactions, designed to help chemical process engineers and students work on chemical process modeling, simulation and optimization projects within a user-friendly environment.

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

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.

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.

Surfer - Surf News, Fantasy Surfer, Photos, Video and Forecasting.