Calcpad

Calcpad is a tool for writing engineering calculation sheets: you type formulas and variables in plain text, including units, and it computes and displays a formatted report with the formulas, substitutions and results. You can add conditions, loops, plots and tables, and save a sheet as a reusable template. Structural engineers use it to build standard design calculations — beams, columns, bolts and connections — as a free alternative to Mathcad. It runs on Windows and there is also a browser version.